patch 9.0.1147: cannot access a class member in a compiled function

Problem:    Cannot access a class member in a compiled function.
Solution:   Implement looking up a class member.
diff --git a/src/testdir/test_vim9_class.vim b/src/testdir/test_vim9_class.vim
index 60730c4..a55671b 100644
--- a/src/testdir/test_vim9_class.vim
+++ b/src/testdir/test_vim9_class.vim
@@ -439,6 +439,11 @@
       TextPos.AddToCounter(3)
       assert_equal(3, TextPos.counter)
       assert_fails('echo TextPos.noSuchMember', 'E1338:')
+      
+      def GetCounter(): number
+        return TextPos.counter
+      enddef
+      assert_equal(3, GetCounter())
 
       assert_fails('TextPos.noSuchMember = 2', 'E1337:')
       assert_fails('TextPos.counter = 5', 'E1335:')