Remove region space memory protection before logging heap corruption.

During heap corruption logging, before reading memory from the region
space (to produce debugging information), make sure all of the space's
pages are readable to prevent a memory protection fault (which would
interrupt debug logging.

Test: art/test.py
Bug: 74064045
Change-Id: I6c804abef7fae602b80c0a2d1020ce870fa6b681