[debug] implement intuitive semantics for stepping over await call.

test/mjsunit/harmony/async-function-debug-scopes.js

Index: test/mjsunit/harmony/async-function-debug-scopes.js
diff --git a/test/mjsunit/harmony/async-function-debug-scopes.js b/test/mjsunit/harmony/async-function-debug-scopes.js
index 33f7716d07de5f148cf4ad77bdca513418042122..3d72549d2ac7b9d64ce500187a72dee21121c68e 100644
--- a/test/mjsunit/harmony/async-function-debug-scopes.js
+++ b/test/mjsunit/harmony/async-function-debug-scopes.js
@@ -501,7 +501,6 @@ function CheckFastAllScopes(scopes, exec_state) {
 // Check that the scope chain contains the expected types of scopes.
 function CheckScopeChain(scopes, exec_state) {
   var all_scopes = exec_state.frame().allScopes();
-  assertEquals(scopes.length, exec_state.frame().scopeCount());
   assertEquals(
       scopes.length, all_scopes.length, "FrameMirror.allScopes length");
   for (var i = 0; i < scopes.length; i++) {