Oilpan: Prepare to move EventQueue and its subclasses to Oilpan heap.

This CL removes WTF_MAKE_FAST_ALLOCATED in TimerBase for Oilpan because
new/delete defined by it conflict with new/delete defined by GarbageCollected in
DOMWindowEventQueueTimer.

BUG=

Review URL: https://codereview.chromium.org/331623002

git-svn-id: svn://svn.chromium.org/blink/trunk@176064 bbb929c8-8fbe-4397-9dbb-9b2b20218538