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_cd.vim b/src/testdir/test_cd.vim
index f43f27c..bd6e3d9 100644
--- a/src/testdir/test_cd.vim
+++ b/src/testdir/test_cd.vim
@@ -4,7 +4,7 @@
 
 func Test_cd_large_path()
   " This used to crash with a heap write overflow.
-  call assert_fails('cd ' . repeat('x', 5000), 'E472:')
+  call assert_fails('cd ' . repeat('x', 5000), 'E344:')
 endfunc
 
 func Test_cd_up_and_down()
@@ -93,7 +93,7 @@
   call assert_equal('testdir', fnamemodify(getcwd(1, 1), ':t'))
 
   " Error case
-  call assert_fails("call chdir('dir-abcd')", 'E472:')
+  call assert_fails("call chdir('dir-abcd')", 'E344:')
   silent! let d = chdir("dir_abcd")
   call assert_equal("", d)
   " Should not crash