patch 8.2.3268: cannot use a block with :autocmd like with :command

Problem:    Cannot use a block with :autocmd like with :command.
Solution:   Add support for a {} block after :autocmd. (closes #8620)
diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index 8abf911..4a7dd60 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
Binary files differ