When you have in async test (test with `done` argument) jasmine will 
execute the next test synchronously in the done handle. This makes sense
for most tests, but now with zones. With zones running next test 
synchronously means that the current zone does not get cleared. This 
results in a chain of nested zones, which makes it hard to reason about 
it. We override the `clearStack` method which forces jasmine to always 
drain the stack before next test gets executed.

This rewrites the (set/clear)Timeout/Interval/Immediate method to render
information in WTF. It also makes the code more explicit, by removing
the need for bind method and instead creating explicit callbacks. The
resulting code is faster, and easier to read and reason about.

setTimeout/clearTimeout and requeustAnimationFrame/cancelAnimationFrame
have same semantics, so now they share the same code path.