fix(specs): change spec scheduler back to setTimeout

Summary:
Adds a new `npm run test-window` that will launch specs in a window so you
can use the debugger

The spec window wouldn't close because `onbeforeunload` was unnecessarily
preventing close. This circumvents this in spec mode.

Most significantly I discovered we can't use the synchronous timer for the
promise scheduler anymore. Suppose you do:

```
it('should error', async () => {
  try {
    await doSomething()
    throw new Error("doSomething should have thrown!")
  } catch (err) {
    expect(err.message).toMatch(/my message/)
  }
})
```

The way async/await is transpiled, when `doSomething` throws, the error
will propagate all the way back up to the uncaughtPromiseException handler
before the `catch` gets called and registered. The transpilation method
assumes that when the function gets executed it can synchrously advance
beyond the call before the `then` or `catch` resolve. When the promise
scheduler is synchronous this doesn't happen.

I chose to use `setTimeout` instead of `process.nextTick` or
`setImmediate` as the promise scheduler. `setTimeout` seems to work better
with Chrome's async function call stacks. `nextTick` and `setImmediate`,
being Node methods, skip Chrome's async watchers.

Test Plan:
I talked with Juan about these changes, in an upcoming diff he will be
testing these in the context of our broader test suite.

Reviewers: mark, khamidou, halla, spang, juan

Reviewed By: juan

Differential Revision: https://phab.nylas.com/D3779

package.json

@@ -109,6 +109,7 @@
   "packageDependencies": {},
   "scripts": {
     "test": "electron . --test --enable-logging",
+    "test-window": "electron . --test=window --enable-logging",
     "start": "electron . --dev --enable-logging",
     "lint": "script/grunt lint",
     "build": "script/grunt build",

spec/n1-spec-runner/n1-gui-reporter.cjsx

@@ -151,7 +151,7 @@ class N1GuiReporter extends React.Component
     </div>
 
   onReloadSpecs: =>
-    require('electron').ipcRenderer.send('call-webcontents-method', 'reload')
+    require('electron').remote.getCurrentWindow().reload()
 
 
 class SuiteResultView extends React.Component

spec/n1-spec-runner/time-override.coffee

@@ -33,6 +33,7 @@ class TimeOverride
   @enableSpies = =>
     window.advanceClock = @advanceClock
 
+    window.originalSetTimeout = window.setTimeout
     window.originalSetInterval = window.setInterval
     spyOn(window, "setTimeout").andCallFake @_fakeSetTimeout
     spyOn(window, "clearTimeout").andCallFake @_fakeClearTimeout
@@ -47,7 +48,7 @@ class TimeOverride
 
   @_setPromiseScheduler: =>
     @originalPromiseScheduler ?= Promise.setScheduler (fn) =>
-      fn()
+      window.originalSetTimeout(fn, 0)
 
   @disableSpies = =>
     window.advanceClock = null

src/window-event-handler.coffee

@@ -35,6 +35,7 @@ class WindowEventHandler
       window.dispatchEvent(new Event('scroll-touch-end'))
 
     window.onbeforeunload = =>
+      if NylasEnv.inSpecMode() then return undefined
       # Don't hide the window here if we don't want the renderer process to be
       # throttled in case more work needs to be done before closing