Check pending exception result in AllocObjectWithAllocator.

Possible previous bug:
Allocation fails due to OOM and the collector transitions.
This caused us to incorrectly retry the allocation with a pending
exception. We now return null if there is a pending exception.

Bug: 17164348

(cherry picked from commit 27f5ae830c5418fa92094608a6e9f693ea88bb69)

Change-Id: I8e7ecafbade7f0b955812df3dd7c94fdc696c856
1 file changed