patch 9.0.0719: too many delete() calls in tests

Problem:    Too many delete() calls in tests.
Solution:   Use deferred delete where possible.
diff --git a/src/testdir/test_swap.vim b/src/testdir/test_swap.vim
index a464940..5237edc 100644
--- a/src/testdir/test_swap.vim
+++ b/src/testdir/test_swap.vim
@@ -16,7 +16,7 @@
 	      \ 'line 2 Abcdefghij',
 	      \ 'line 3 Abcdefghij',
 	      \ 'end of testfile']
-  call writefile(content, 'Xtest1')
+  call writefile(content, 'Xtest1', 'D')
 
   "  '.', swap file in the same directory as file
   set dir=.,~
@@ -30,7 +30,7 @@
   " './dir', swap file in a directory relative to the file
   set dir=./Xtest2,.,~
 
-  call mkdir("Xtest2")
+  call mkdir("Xtest2", 'R')
   edit Xtest1
   call assert_equal([], glob(swfname, 1, 1, 1))
   let swfname = "Xtest2/Xtest1.swp"
@@ -40,7 +40,7 @@
   " 'dir', swap file in directory relative to the current dir
   set dir=Xtest.je,~
 
-  call mkdir("Xtest.je")
+  call mkdir("Xtest.je", 'R')
   call writefile(content, 'Xtest2/Xtest3')
   edit Xtest2/Xtest3
   call assert_equal(["Xtest2/Xtest3"], glob("Xtest2/*", 1, 1, 1))
@@ -49,9 +49,6 @@
   call assert_equal([swfname], glob("Xtest.je/*", 1, 1, 1))
 
   set dir&
-  call delete("Xtest1")
-  call delete("Xtest2", "rf")
-  call delete("Xtest.je", "rf")
 endfunc
 
 func Test_swap_group()
@@ -135,7 +132,7 @@
   let info = swapinfo('doesnotexist')
   call assert_equal('Cannot open file', info.error)
 
-  call writefile(['burp'], 'Xnotaswapfile')
+  call writefile(['burp'], 'Xnotaswapfile', 'D')
   let info = swapinfo('Xnotaswapfile')
   call assert_equal('Cannot read file', info.error)
   call delete('Xnotaswapfile')
@@ -143,7 +140,6 @@
   call writefile([repeat('x', 10000)], 'Xnotaswapfile')
   let info = swapinfo('Xnotaswapfile')
   call assert_equal('Not a swap file', info.error)
-  call delete('Xnotaswapfile')
 endfunc
 
 func Test_swapname()
@@ -191,7 +187,7 @@
   " Close the file and recreate the swap file.
   " Now editing the file will run into the process still existing
   quit
-  call writefile(swapfile_bytes, swapfile_name)
+  call writefile(swapfile_bytes, swapfile_name, 'D')
   let s:swap_choice = 'e'
   let s:swapname = ''
   split XswapfileText
@@ -219,7 +215,6 @@
   call assert_equal(fnamemodify(swapfile_name, ':t'), fnamemodify(s:swapname, ':t'))
 
   call delete('XswapfileText')
-  call delete(swapfile_name)
   augroup test_swapfile_delete
     autocmd!
   augroup END
@@ -233,7 +228,7 @@
     autocmd SwapExists * let v:swapchoice = 'r'
   augroup END
 
-  call mkdir('Xswap')
+  call mkdir('Xswap', 'R')
   let $Xswap = 'foo'  " Check for issue #4369.
   set dir=Xswap//
   " Create a valid swapfile by editing a file.
@@ -246,7 +241,7 @@
 
   " Close the file and recreate the swap file.
   quit
-  call writefile(swapfile_bytes, swapfile_name)
+  call writefile(swapfile_bytes, swapfile_name, 'D')
   " Edit the file again. This triggers recovery.
   try
     split Xswap/text
@@ -258,9 +253,6 @@
   call assert_equal(['one', 'two', 'three'], getline(1, 3))
   quit!
 
-  call delete('Xswap/text')
-  call delete(swapfile_name)
-  call delete('Xswap', 'd')
   unlet $Xswap
   set dir&
   augroup test_swap_recover
@@ -288,7 +280,7 @@
   " Close and delete the file and recreate the swap file.
   quit
   call delete('Xtest.scr')
-  call writefile(swapfile_bytes, swapfile_name)
+  call writefile(swapfile_bytes, swapfile_name, 'D')
   " Edit the file again. This triggers recovery.
   try
     split Xtest.scr
@@ -301,7 +293,6 @@
   quit!
 
   call delete('Xtest.scr')
-  call delete(swapfile_name)
   augroup test_swap_recover_ext
     autocmd!
   augroup END
@@ -329,7 +320,7 @@
   " Close and delete the file and recreate the swap file.
   quit
   call delete('Xtest.scr')
-  call writefile(swapfile_bytes, swapfile_name)
+  call writefile(swapfile_bytes, swapfile_name, 'D')
   " Split edit the file again. This should fail to open the window
   try
     split Xtest.scr
@@ -340,7 +331,6 @@
   call assert_equal(1, winnr('$'))
 
   call delete('Xtest.scr')
-  call delete(swapfile_name)
 
   augroup test_swap_splitwin
       autocmd!
@@ -352,7 +342,7 @@
 func Test_swap_prompt_splitwin()
   CheckRunVimInTerminal
 
-  call writefile(['foo bar'], 'Xfile1')
+  call writefile(['foo bar'], 'Xfile1', 'D')
   edit Xfile1
   preserve  " should help to make sure the swap file exists
 
@@ -387,13 +377,12 @@
   call StopVimInTerminal(buf)
 
   %bwipe!
-  call delete('Xfile1')
 endfunc
 
 func Test_swap_symlink()
   CheckUnix
 
-  call writefile(['text'], 'Xtestfile')
+  call writefile(['text'], 'Xtestfile', 'D')
   silent !ln -s -f Xtestfile Xtestlink
 
   set dir=.
@@ -404,7 +393,7 @@
   call assert_match('Xtestfile\.swp$', s:swapname())
   bwipe!
 
-  call mkdir('Xswapdir')
+  call mkdir('Xswapdir', 'R')
   exe 'set dir=' . getcwd() . '/Xswapdir//'
 
   " Check that this also works when 'directory' ends with '//'
@@ -413,9 +402,7 @@
   bwipe!
 
   set dir&
-  call delete('Xtestfile')
   call delete('Xtestlink')
-  call delete('Xswapdir', 'rf')
 endfunc
 
 func s:get_unused_pid(base)
@@ -467,7 +454,7 @@
   " Change the process ID to avoid the "still running" warning.
   let swapfile_bytes[24:27] = s:pid_to_blob(s:get_unused_pid(
         \ s:blob_to_pid(swapfile_bytes[24:27])))
-  call writefile(swapfile_bytes, swapfile_name)
+  call writefile(swapfile_bytes, swapfile_name, 'D')
   edit Xtest.scr
   " will end up using the same swap file after deleting the existing one
   call assert_equal(swapfile_name, swapname('%'))
@@ -491,7 +478,6 @@
   bwipe!
 
   call delete('Xtest.scr')
-  call delete(swapfile_name)
   augroup test_swap_recover_ext
     autocmd!
   augroup END
@@ -520,13 +506,13 @@
 
 " Test for the v:swapchoice variable
 func Test_swapchoice()
-  call writefile(['aaa', 'bbb'], 'Xfile5')
+  call writefile(['aaa', 'bbb'], 'Xfile5', 'D')
   edit Xfile5
   preserve
   let swapfname = swapname('')
   let b = readblob(swapfname)
   bw!
-  call writefile(b, swapfname)
+  call writefile(b, swapfname, 'D')
 
   autocmd! SwapExists
 
@@ -565,7 +551,6 @@
   %bw!
   call assert_false(filereadable(swapfname))
 
-  call delete('Xfile5')
   call delete(swapfname)
   augroup test_swapchoice
     autocmd!