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)
diff --git a/src/testdir/test_compiler.vim b/src/testdir/test_compiler.vim
index ecf8083..06a37c9 100644
--- a/src/testdir/test_compiler.vim
+++ b/src/testdir/test_compiler.vim
@@ -4,9 +4,7 @@
 source shared.vim
 
 func Test_compiler()
-  if !executable('perl')
-    return
-  endif
+  CheckExecutable perl
   CheckFeature quickfix
 
   " $LANG changes the output of Perl.