[debugger] remove step count parameter from prepare step.

test/mjsunit/es6/debug-stepin-microtasks.js

Index: test/mjsunit/es6/debug-stepin-microtasks.js
diff --git a/test/mjsunit/es6/debug-stepin-microtasks.js b/test/mjsunit/es6/debug-stepin-microtasks.js
index 98510ff52be153373b1fa29624377c17c823b33e..6a7c5536dcd92049d8e2a1dcda19987eecf43784 100644
--- a/test/mjsunit/es6/debug-stepin-microtasks.js
+++ b/test/mjsunit/es6/debug-stepin-microtasks.js
@@ -26,9 +26,9 @@ function listener(event, exec_state, event_data, data) {
                  "Unexpected pause at: " + source + "\n" +
                  "Expected: // Break " + break_count + ".");
       if (source.indexOf("StepOver.") !== -1) {
-        exec_state.prepareStep(Debug.StepAction.StepNext, 1);
+        exec_state.prepareStep(Debug.StepAction.StepNext);
       } else {
-        exec_state.prepareStep(Debug.StepAction.StepIn, 1);
+        exec_state.prepareStep(Debug.StepAction.StepIn);
       }
       ++break_count;
     }