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/testdir/Make_all.mak b/src/testdir/Make_all.mak
index 1ac29b1..886bb08 100644
--- a/src/testdir/Make_all.mak
+++ b/src/testdir/Make_all.mak
@@ -37,6 +37,7 @@
 TEST_VIM9 = \
 	test_vim9_assign \
 	test_vim9_builtin \
+	test_vim9_class \
 	test_vim9_cmd \
 	test_vim9_disassemble \
 	test_vim9_expr \
@@ -48,6 +49,7 @@
 TEST_VIM9_RES = \
 	test_vim9_assign.res \
 	test_vim9_builtin.res \
+	test_vim9_class.res \
 	test_vim9_cmd.res \
 	test_vim9_disassemble.res \
 	test_vim9_expr.res \