patch 8.1.2129: using hard coded executable path in test

Problem:    Using hard coded executable path in test.
Solution:   Use v:progpath. Use $VIMRUNTIME instead of "runtime". (James
            McCoy, closes #5025)
diff --git a/src/testdir/test49.vim b/src/testdir/test49.vim
index bd60514..b6f6f6b 100644
--- a/src/testdir/test49.vim
+++ b/src/testdir/test49.vim
@@ -1,6 +1,6 @@
 " Vim script language tests
 " Author:	Servatius Brandt <Servatius.Brandt@fujitsu-siemens.com>
-" Last Change:	2019 May 24
+" Last Change:	2019 Oct 08
 
 "-------------------------------------------------------------------------------
 " Test environment							    {{{1
@@ -456,7 +456,7 @@
     " messing up the user's viminfo file.
     let redirect = a:0 ?
 	\ " -c 'au VimLeave * redir END' -c 'redir\\! >" . a:1 . "'" : ""
-    exec "!echo '" . debug_quits . "q' | ../vim -u NONE -N -Xes" . redirect .
+    exec "!echo '" . debug_quits . "q' | " .. v:progpath .. " -u NONE -N -Xes" . redirect .
 	\ " -c 'debuggreedy|set viminfo+=nviminfo'" .
 	\ " -c 'let ExtraVimBegin = " . extra_begin . "'" .
 	\ " -c 'let ExtraVimResult = \"" . resultfile . "\"'" . breakpoints .
diff --git a/src/testdir/test_compiler.vim b/src/testdir/test_compiler.vim
index 40d3cdb..06522d7 100644
--- a/src/testdir/test_compiler.vim
+++ b/src/testdir/test_compiler.vim
@@ -39,9 +39,9 @@
 
 func Test_compiler_without_arg()
   let a=split(execute('compiler'))
-  call assert_match('^.*runtime/compiler/ant.vim$',   a[0])
-  call assert_match('^.*runtime/compiler/bcc.vim$',   a[1])
-  call assert_match('^.*runtime/compiler/xmlwf.vim$', a[-1])
+  call assert_match($VIMRUNTIME .. '/compiler/ant.vim$',   a[0])
+  call assert_match($VIMRUNTIME .. '/compiler/bcc.vim$',   a[1])
+  call assert_match($VIMRUNTIME .. '/compiler/xmlwf.vim$', a[-1])
 endfunc
 
 func Test_compiler_completion()
diff --git a/src/testdir/test_spell.vim b/src/testdir/test_spell.vim
index a44d955..5231266 100644
--- a/src/testdir/test_spell.vim
+++ b/src/testdir/test_spell.vim
@@ -130,18 +130,18 @@
   new
 
   set enc=latin1 spell spelllang=en
-  call assert_match("^\nfile: .*/runtime/spell/en.latin1.spl\n$", execute('spellinfo'))
+  call assert_match("^\nfile: " .. $VIMRUNTIME .. "/spell/en.latin1.spl\n$", execute('spellinfo'))
 
   set enc=cp1250 spell spelllang=en
-  call assert_match("^\nfile: .*/runtime/spell/en.ascii.spl\n$", execute('spellinfo'))
+  call assert_match("^\nfile: " .. $VIMRUNTIME .. "/spell/en.ascii.spl\n$", execute('spellinfo'))
 
   set enc=utf-8 spell spelllang=en
-  call assert_match("^\nfile: .*/runtime/spell/en.utf-8.spl\n$", execute('spellinfo'))
+  call assert_match("^\nfile: " .. $VIMRUNTIME .. "/spell/en.utf-8.spl\n$", execute('spellinfo'))
 
   set enc=latin1 spell spelllang=en_us,en_nz
   call assert_match("^\n" .
-                 \  "file: .*/runtime/spell/en.latin1.spl\n" .
-                 \  "file: .*/runtime/spell/en.latin1.spl\n$", execute('spellinfo'))
+                 \  "file: " .. $VIMRUNTIME .. "/spell/en.latin1.spl\n" .
+                 \  "file: " .. $VIMRUNTIME .. "/spell/en.latin1.spl\n$", execute('spellinfo'))
 
   set spell spelllang=
   call assert_fails('spellinfo', 'E756:')