patch 8.1.2011: more functions can be used as methods

Problem:    More functions can be used as methods.
Solution:   Make various functions usable as a method.  Make the window
            command test faster.
diff --git a/src/testdir/test_messages.vim b/src/testdir/test_messages.vim
index f122917..bcfcdd2 100644
--- a/src/testdir/test_messages.vim
+++ b/src/testdir/test_messages.vim
@@ -90,7 +90,7 @@
   if has('float')
     call assert_equal("\n1.23 IgNoRe", execute(':echoerr 1.23 "IgNoRe"'))
   endif
-  call test_ignore_error('<lambda>')
+  eval '<lambda>'->test_ignore_error()
   call assert_match("function('<lambda>\\d*')", execute(':echoerr {-> 1234}'))
   call test_ignore_error('RESET')
 endfunc