patch 8.2.2300: Vim9: wrong order on type stack when using dict

Problem:    Vim9: wrong order on type stack when using dict.
Solution:   Generate constants before a dict. (closes #7619)

src/testdir/test_vim9_expr.vim

@@ -1094,6 +1094,8 @@ def Test_expr5()
 
       $ENVVAR = 'env'
       assert_equal('aenv', 'a' .. $ENVVAR)
+
+      assert_equal('val', '' .. {key: 'val'}['key'])
   END
   CheckDefAndScriptSuccess(lines)
 enddef