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

test/debugger/debug/regress/regress-crbug-568477-1.js

Index: test/debugger/debug/regress/regress-crbug-568477-1.js
diff --git a/test/debugger/debug/regress/regress-crbug-568477-1.js b/test/debugger/debug/regress/regress-crbug-568477-1.js
index bf1aacb88e6c55035787252a3a31ce9b5cef07b3..f9a7ba4275bb80ad51806dc931c943061ba38453 100644
--- a/test/debugger/debug/regress/regress-crbug-568477-1.js
+++ b/test/debugger/debug/regress/regress-crbug-568477-1.js
@@ -10,8 +10,9 @@ var log = [];
 function listener(event, exec_state, event_data, data) {
   if (event != Debug.DebugEvent.Break) return;
   try {
-    log.push(exec_state.frame(0).sourceLineText().trimLeft());
-    exec_state.prepareStep(Debug.StepAction.StepNext);
+    var line = exec_state.frame(0).sourceLineText().trimLeft();
+    log.push(line);
+    if (line == "debugger;") exec_state.prepareStep(Debug.StepAction.StepNext);
   } catch (e) {
     %AbortJS(e + "\n" + e.stack);
   }