patch 8.2.1434: Vim9: crash when lambda uses outer function argument

Problem:    Vim9: crash when lambda uses outer function argument.
Solution:   Set the flag that the outer context is used.
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index d6313d3..795ea75 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -1443,6 +1443,16 @@
         }
 enddef
 
+def LambdaUsingArg(x: number): func
+  return {->
+            # some comment
+            x == 1
+            # some comment
+            ||
+            x == 2
+        }
+enddef
+
 def Test_expr7_lambda()
   let La = { -> 'result'}
   assert_equal('result', La())
@@ -1481,6 +1491,9 @@
   assert_equal(true, LambdaWithComments()(2))
   assert_equal(false, LambdaWithComments()(3))
 
+  assert_equal(false, LambdaUsingArg(0)())
+  assert_equal(true, LambdaUsingArg(1)())
+
   call CheckDefFailure(["filter([1, 2], {k,v -> 1})"], 'E1069:')
 enddef