patch 8.1.0711: test files still use function!

Problem:    Test files still use function!.
Solution:   Remove the exclamation mark.  Fix overwriting a function.
diff --git a/src/testdir/test_display.vim b/src/testdir/test_display.vim
index 48b7a23..e0e3e3b 100644
--- a/src/testdir/test_display.vim
+++ b/src/testdir/test_display.vim
@@ -5,7 +5,7 @@
 
 source view_util.vim
 
-func! Test_display_foldcolumn()
+func Test_display_foldcolumn()
   if !has("folding")
     return
   endif
@@ -38,7 +38,7 @@
   quit!
 endfunc
 
-func! Test_display_foldtext_mbyte()
+func Test_display_foldtext_mbyte()
   if !has("folding") || !has("multi_byte")
     return
   endif