Try always mocking Date.now in our global spec helper

spec/pane-spec.js

@@ -1350,7 +1350,6 @@ describe('Pane', () => {
     let editor1, pane, eventCount
 
     beforeEach(async () => {
-      jasmine.useMockClock()
       editor1 = await atom.workspace.open('sample.txt', {pending: true})
       pane = atom.workspace.getActivePane()
       eventCount = 0

spec/spec-helper.coffee

@@ -65,6 +65,7 @@ beforeEach ->
 
   window.resetTimeouts()
   spyOn(_._, "now").andCallFake -> window.now
+  spyOn(Date, 'now').andCallFake(-> window.now)
   spyOn(window, "setTimeout").andCallFake window.fakeSetTimeout
   spyOn(window, "clearTimeout").andCallFake window.fakeClearTimeout
 
@@ -179,6 +180,7 @@ jasmine.useRealClock = ->
   jasmine.unspy(window, 'setTimeout')
   jasmine.unspy(window, 'clearTimeout')
   jasmine.unspy(_._, 'now')
+  jasmine.unspy(Date, 'now')
 
 # The clock is halfway mocked now in a sad and terrible way... only setTimeout
 # and clearTimeout are included. This method will also include setInterval. We
@@ -186,8 +188,6 @@ jasmine.useRealClock = ->
 jasmine.useMockClock = ->
   spyOn(window, 'setInterval').andCallFake(fakeSetInterval)
   spyOn(window, 'clearInterval').andCallFake(fakeClearInterval)
-  spyOn(Date, 'now').andCallFake(-> window.now)
-
 
 addCustomMatchers = (spec) ->
   spec.addMatchers