patch 8.2.2060: check for features implemented with "if"

Problem:    Check for features implemented with "if".
Solution:   Use the Check commands. (Ken Takata, closes #7383)

src/testdir/test_autocmd.vim

@@ -1689,9 +1689,7 @@ func Test_change_mark_in_autocmds()
 endfunc
 
 func Test_Filter_noshelltemp()
-  if !executable('cat')
+  CheckExecutable cat
-    return
-  endif
 
   enew!
   call setline(1, ['a', 'b', 'c', 'd'])

src/testdir/test_compiler.vim

@@ -4,9 +4,7 @@ source check.vim
 source shared.vim
 
 func Test_compiler()
-  if !executable('perl')
+  CheckExecutable perl
-    return
-  endif
   CheckFeature quickfix
 
   " $LANG changes the output of Perl.

src/testdir/test_delete.vim

@@ -1,5 +1,7 @@
 " Test for delete().
 
+source check.vim
+
 func Test_file_delete()
   split Xfile
   call setline(1, ['a', 'b'])
@@ -41,9 +43,7 @@ func Test_recursive_delete()
 endfunc
 
 func Test_symlink_delete()
-  if !has('unix')
+  CheckUnix
-    return
-  endif
   split Xfile
   call setline(1, ['a', 'b'])
   wq
@@ -56,9 +56,7 @@ func Test_symlink_delete()
 endfunc
 
 func Test_symlink_dir_delete()
-  if !has('unix')
+  CheckUnix
-    return
-  endif
   call mkdir('Xdir1')
   silent !ln -s Xdir1 Xlink
   call assert_true(isdirectory('Xdir1'))
@@ -70,9 +68,7 @@ func Test_symlink_dir_delete()
 endfunc
 
 func Test_symlink_recursive_delete()
-  if !has('unix')
+  CheckUnix
-    return
-  endif
   call mkdir('Xdir3')
   call mkdir('Xdir3/subdir')
   call mkdir('Xdir4')

src/testdir/test_diffmode.vim

@@ -621,9 +621,7 @@ func Test_diff_move_to()
 endfunc
 
 func Test_diffexpr()
-  if !executable('diff')
+  CheckExecutable diff
-    return
-  endif
 
   func DiffExpr()
     " Prepent some text to check diff type detection

src/testdir/test_expr.vim

@@ -543,9 +543,7 @@ endfunc
 
 " Test for command-line completion of expressions
 func Test_expr_completion()
-  if !has('cmdline_compl')
+  CheckFeature cmdline_compl
-    return
-  endif
   for cmd in [
 	\ 'let a = ',
 	\ 'const a = ',

src/testdir/test_fold.vim

@@ -95,9 +95,7 @@ func Test_indent_fold2()
 endfunc
 
 func Test_manual_fold_with_filter()
-  if !executable('cat')
+  CheckExecutable cat
-    return
-  endif
   for type in ['manual', 'marker']
     exe 'set foldmethod=' . type
     new

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2060,
 /**/
     2059,
 /**/