StrictMode: check max-offenses-per-loop earlier, before allocations

Previously a tight loop of StrictMode violations would still allocate
Exception objects and populate their stack frames, just to orphan them
later when checking the max-10-violations-per-loop constraint.

With this patch, we do that check _before_ allocating any memory.

Change-Id: Iae96aba33f8fcc6a8ec5838a231aecc08e95122d