patch 8.2.4892: test failures because of changed error messages

Problem:    Test failures because of changed error messages.
Solution:   Adjust the exptected error messages.
diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index c5c3eb9..7166b13 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -1527,7 +1527,7 @@
       source Xtestscript.vim
     catch /E684/
       # function name should contain <SNR> every time
-      assert_match('E684: list index out of range', v:exception)
+      assert_match('E684: List index out of range', v:exception)
       assert_match('function <SNR>\d\+_Func, line 1', v:throwpoint)
     endtry
   endfor