[DevTools] New harness for inspector-protocol layout tests

third_party/WebKit/LayoutTests/inspector-protocol/cpu-profiler/stop-without-preceeding-start.js

+(async function() {
+  let {page, session, Protocol} = await InspectorTest.startBlank(
+      'Test that profiler doesn\'t crash when we call stop without preceeding start.');
+  var messageObject = await Protocol.Profiler.stop();
+  InspectorTest.expectedError('ProfileAgent.stop', messageObject);
+  InspectorTest.completeTest();
+})();