patch 9.0.1556: Vim9: error for missing "return" after "throw"

Problem:    Vim9: error for missing "return" after "throw".
Solution:   Set had_return flag for "throw". (closes #12262)
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 2965afa..ffb8de4 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
Binary files differ