vim-patch:9.0.2045: tests: checking for swap files takes time

Problem:  tests: checking for swap files takes time
Solution: don't check for swap files  when test has been skipped

Check for swap files takes a considerable about of time, so don't do
that for skipped tests to avoid wasting time.

closes: vim/vim#13371

a0e1f06f04

test/old/testdir/runtest.vim

@@ -231,6 +231,8 @@ func RunTheTest(test)
     endtry
   endif
 
+  let skipped = v:false
+
   au VimLeavePre * call EarlyExit(g:testfunc)
   if a:test =~ 'Test_nocatch_'
     " Function handles errors itself.  This avoids skipping commands after the
@@ -240,6 +242,7 @@ func RunTheTest(test)
     if g:skipped_reason != ''
       call add(s:messages, '    Skipped')
       call add(s:skipped, 'SKIPPED ' . a:test . ': ' . g:skipped_reason)
+      let skipped = v:true
     endif
   else
     try
@@ -247,6 +250,7 @@ func RunTheTest(test)
     catch /^\cskipped/
       call add(s:messages, '    Skipped')
       call add(s:skipped, 'SKIPPED ' . a:test . ': ' . substitute(v:exception, '^\S*\s\+', '',  ''))
+      let skipped = v:true
     catch
       call add(v:errors, 'Caught exception in ' . a:test . ': ' . v:exception . ' @ ' . v:throwpoint)
     endtry
@@ -342,6 +346,7 @@ func RunTheTest(test)
     endif
   endwhile
 
+  if !skipped
     " Check if the test has left any swap files behind.  Delete them before
     " running tests again, they might interfere.
     let swapfiles = s:GetSwapFileList()
@@ -351,6 +356,7 @@ func RunTheTest(test)
         call delete(name)
       endfor
     endif
+  endif
 endfunc
 
 function Delete_Xtest_Files()