patch 9.0.1031: Vim9 class is not implemented yet

Problem:    Vim9 class is not implemented yet.
Solution:   Add very basic class support.
diff --git a/src/testing.c b/src/testing.c
index d76d098..74b6b0e 100644
--- a/src/testing.c
+++ b/src/testing.c
@@ -1101,6 +1101,8 @@
 	case VAR_SPECIAL:
 	case VAR_STRING:
 	case VAR_INSTR:
+	case VAR_CLASS:
+	case VAR_OBJECT:
 	    break;
 	case VAR_JOB:
 #ifdef FEAT_JOB_CHANNEL