Revert "Revert "Avoid adding region space bitmap to heap bitmap""

The issue was that hprof dumping could run in the middle of non CC
GC. This meant the allocation stack and live bitmap could both visit
the same object. The solution is to use a GC critical section.

Bug: 34967844

Test: test-art-host

This reverts commit 215835da.

Change-Id: I99e65ff31ece74aa94fc55cc7480e27c1e39661b