patch 8.2.1183: assert_fails() checks the last error message
Problem: assert_fails() checks the last error message.
Solution: Check the first error, it is more relevant. Fix all the tests
that rely on the old behavior.
diff --git a/src/testdir/test_window_cmd.vim b/src/testdir/test_window_cmd.vim
index aa619cd..5506dbe 100644
--- a/src/testdir/test_window_cmd.vim
+++ b/src/testdir/test_window_cmd.vim
@@ -569,7 +569,7 @@
au * 0 vs xxx
arg 0
argadd
- call assert_fails("all", "E249:")
+ call assert_fails("all", "E242:")
au!
bwipe xxx
call assert_equal(&columns, winwidth(0))