fix(flaky-test): Add time to beforeEach() to allow plugins to load on first pass. (#3025)

Loading plugins in beforeEach seems unwise: the it() blocks potentially run against different environments. In particular the first it() block runs with the timer already worn down by the plugin load and often the timeout hits on my mac air before the test passes.Until we can restructure this code a longer timeout avoids flaky tests.

Author: johnjbarton

test/unit/server.spec.js

@@ -17,7 +17,10 @@ describe('server', () => {
   var fileListOnResolve = fileListOnReject = mockLauncher = null
   var mockFileList = mockWebServer = mockSocketServer = mockExecutor = doneSpy = null
 
-  beforeEach(() => {
+  // Use regular function not arrow so 'this' is mocha 'this'.
+  beforeEach(function () {
+    // The first call to new Server() loads plugins and it can take >2000ms.
+    this.timeout(4000)
     browserCollection = new BrowserCollection()
     doneSpy = sinon.spy()