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/evalvars.c b/src/evalvars.c
index 31cc760..d946669 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -2264,6 +2264,8 @@
 	case VAR_JOB:
 	case VAR_CHANNEL:
 	case VAR_INSTR:
+	case VAR_CLASS:
+	case VAR_OBJECT:
 	    break;
 
 	case VAR_BLOB: