patch 9.1.0391: Vim9: could improve testing

Problem:  Vim9: could improve testing
          (Ernie Rael)
Solution: Support defcompile for test_override() to
          improve testing (Yegappan Lakshmanan)

fixes: #14553
closes: #14712

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testing.c b/src/testing.c
index 33de3a5..3e9e077 100644
--- a/src/testing.c
+++ b/src/testing.c
@@ -1051,6 +1051,8 @@
 	ml_get_alloc_lines = val;
     else if (STRCMP(name, (char_u *)"autoload") == 0)
 	override_autoload = val;
+    else if (STRCMP(name, (char_u *)"defcompile") == 0)
+	override_defcompile = val;
     else if (STRCMP(name, (char_u *)"ALL") == 0)
     {
 	disable_char_avail_for_testing = FALSE;