patch 9.1.1057: Superfluous cleanup steps in test_ins_complete.vim

Problem:  Superfluous cleanup steps in test_ins_complete.vim.
Solution: Remove unnecessary :bw! and :autocmd! commands.
          Also remove unnecessary STRLEN() in insexpand.c
          (zeertzjq)

closes: #16542

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_ins_complete.vim b/src/testdir/test_ins_complete.vim
index e4bc98a..d0f90c8 100644
--- a/src/testdir/test_ins_complete.vim
+++ b/src/testdir/test_ins_complete.vim
@@ -2989,7 +2989,6 @@
   call assert_false(has_key(g:compl_info, 'matches'))
 
   bw!
-  bw!
   unlet g:what
   delfunc ShownInfo
   set cot&
@@ -3020,7 +3019,6 @@
   call assert_equal({}, g:compl_info)
 
   bw!
-  bw!
   delfunc ShownInfo
   set cot&
 endfunc
@@ -3082,7 +3080,7 @@
   call assert_equal("hello  fobar wo", getline('.'))
   call feedkeys("\<C-E>\<ESC>", 'tx')
 
-  " confrim
+  " confirm
   call feedkeys("S\<C-X>\<C-O>f\<C-Y>", 'tx')
   call assert_equal("fobar", getline('.'))
   call assert_equal(5, col('.'))
@@ -3135,11 +3133,9 @@
   call assert_equal(5, col('.'))
 
   bw!
-  bw!
   set cot&
   set omnifunc&
   delfunc Omni_test
-  autocmd! CompleteChanged
 endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab nofoldenable