DevTools: fix --debug-devtools flag for npm test

third_party/WebKit/Source/devtools/scripts/npm_test.js

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var childProcess = require("child_process");
 var fs = require("fs");
 var path = require("path");
 var shell = require("child_process").execSync;
 
 var utils = require("./utils");
@@ skipping 215 matching lines @@
 
 function runTests(buildDirectoryPath, useDebugDevtools)
 {
     var testArgs = getInspectorTests().concat([
         "--no-pixel-tests",
         "--build-directory",
         buildDirectoryPath,
     ]);
     if (useDebugDevtools) {
         testArgs.push("--additional-driver-flag=--debug-devtools");
+    } else {
+        console.log("TIP: You can debug a test using: npm run debug-test inspector/test-name.html")
     }
     if (IS_DEBUG_ENABLED) {
         testArgs.push("--additional-driver-flag=--remote-debugging-port=9222");
         testArgs.push("--time-out-ms=6000000");
         console.log("\n=============================================");
         console.log("Go to: http://localhost:9222/");
         console.log("Click on link and in console execute: test()");
         console.log("=============================================\n");
     }
     var args = [BLINK_TEST_PATH].concat(testArgs).concat(getTestFlags());
@@ skipping 12 matching lines @@
 function getInspectorTests()
 {
     var specificTests = process.argv.filter(arg => utils.includes(arg, "inspector"));
     if (specificTests.length)
         return specificTests;
     return [
         "inspector*",
         "http/tests/inspector*",
     ];
 }