Dump inspector traffic to stderr for all tests under inspector/sources/debugger-step

LayoutTests/http/tests/inspector/debugger-test.js

 var initialize_DebuggerTest = function() {
 
 InspectorTest.preloadPanel("sources");
 
 InspectorTest.startDebuggerTest = function(callback, quiet)
 {
+    var testPath = WebInspector.settings.createSetting("testPath", "").get();
+    if (testPath.startsWith("LayoutTests/inspector/sources/debugger-step/"))
+        InspectorTest.startDumpingProtocolMessages();
     console.assert(InspectorTest.debuggerModel.debuggerEnabled(), "Debugger has to be enabled");
     if (quiet !== undefined)
         InspectorTest._quiet = quiet;
     WebInspector.SourcesPanel.show();
 
     InspectorTest.addSniffer(WebInspector.DebuggerModel.prototype, "_pausedScript", InspectorTest._pausedScript, true);
     InspectorTest.addSniffer(WebInspector.DebuggerModel.prototype, "_resumedScript", InspectorTest._resumedScript, true);
     InspectorTest.safeWrap(callback)();
 };
 
@@ skipping 506 matching lines @@
     return self.runtime.instancesPromise(WebInspector.SourcesView.EditorAction).then(function(editorActions) {
         for (var i = 0; i < editorActions.length; ++i) {
             if (editorActions[i] instanceof WebInspector.ScriptFormatterEditorAction)
                 return editorActions[i];
         }
         return null;
     });
 };
 
 };