patch 8.0.1377: cannot call a dict function in autoloaded dict

Problem:    Cannot call a dict function in autoloaded dict.
Solution:   Call get_lval() passing the read-only flag.
diff --git a/src/Makefile b/src/Makefile
index 7ccd766..2a66a02 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -2120,6 +2120,7 @@
 	test_assign \
 	test_autochdir \
 	test_autocmd \
+	test_autoload \
 	test_backspace_opt \
 	test_breakindent \
 	test_bufline \