Refactor suite timing out of Env and into each Reporter

[finishes #45659879]

spec/core/TimerSpec.js

@@ -0,0 +1,13 @@
+describe("Timer", function() {
+  it("reports the time elapsed", function() {
+    var fakeNow = jasmine.createSpy('fake Date.now'),
+        timer = new j$.Timer({now: fakeNow});
+
+    fakeNow.andReturn(100);
+    timer.start();
+
+    fakeNow.andReturn(200);
+
+    expect(timer.elapsed()).toEqual(100);
+  });
+});