patch 8.0.0323: one second pause when running cmdline test

Problem:    When running the command line tests there is a one second wait.
Solution:   Change an Esc to Ctrl-C. (Yegappan Lakshmanan)
diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index 0a5c910..b2beb68 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -353,7 +353,7 @@
   call feedkeys("?MyCmd a\<C-R>=Check_cmdline('?')\<CR>\<Esc>", "xt")
 
   call feedkeys(":call input('Answer?')\<CR>", "t")
-  call feedkeys("MyCmd a\<C-R>=Check_cmdline('@')\<CR>\<Esc>", "xt")
+  call feedkeys("MyCmd a\<C-R>=Check_cmdline('@')\<CR>\<C-C>", "xt")
 
   call feedkeys(":insert\<CR>MyCmd a\<C-R>=Check_cmdline('-')\<CR>\<Esc>", "xt")