[debug-wrapper] adapt stepping tests to inspector behavior.

test/debugger/debug/regress/regress-crbug-568477-2.js

Index: test/debugger/debug/regress/regress-crbug-568477-2.js
diff --git a/test/debugger/debug/regress/regress-crbug-568477-2.js b/test/debugger/debug/regress/regress-crbug-568477-2.js
index 7076f6b6b4d2646eade5a377ca3dad8e0868c87b..0ea4b7ea388815ae1a83ae1a8851139c9296b391 100644
--- a/test/debugger/debug/regress/regress-crbug-568477-2.js
+++ b/test/debugger/debug/regress/regress-crbug-568477-2.js
@@ -6,16 +6,15 @@
 var Debug = debug.Debug;
 var expected = ["debugger;",
                 "var x = y;",
-                "new Promise(f).catch(call_f_with_deeper_stack);",
-                "var a = 1;", "var a = 1;",
                 "debugger;",
                 "var x = y;"];
 
 function listener(event, exec_state, event_data, data) {
   if (event != Debug.DebugEvent.Break) return;
   try {
-    assertEquals(expected.shift(), exec_state.frame(0).sourceLineText().trimLeft());
-    exec_state.prepareStep(Debug.StepAction.StepNext);
+    var line = exec_state.frame(0).sourceLineText().trimLeft();
+    assertEquals(expected.shift(), line);
+    if (line == "debugger;") exec_state.prepareStep(Debug.StepAction.StepNext);
   } catch (e) {
     %AbortJS(e + "\n" + e.stack);
   }