Clear mark-bitmap after compaction

It was mistakenly not being cleared until next GC cycle, in which it
would then immediately be used again, unnecessarily increasing private
dirty.

Bug: 263341475
Bug: 263326265
Bug: 160737021
Test: crystallbal and MPTS
Change-Id: I0e900636431f49bde6368bf8c0d1e28393289d08
2 files changed