Add thread unsafe allocation methods to spaces.

Used by SS/GSS collectors since these run with mutators suspended and
only allocate from a single thread. Added AllocThreadUnsafe to
BumpPointerSpace and RosAllocSpace. Added AllocThreadUnsafe which uses
current runs as thread local runs for a thread unsafe allocation.
Added code to revoke current runs which are the same idx as thread
local runs.

Changed:
The number of thread local runs in each thread is now the the number
of thread local runs in RosAlloc instead of the number of size
brackets.

Total GC time / time on EvaluateAndApplyChanges.
TLAB SS:
Before: 36.7s / 7254
After: 16.1s / 4837

TLAB GSS:
Before: 6.9s / 3973
After: 5.7s / 3778

Bug: 8981901

Change-Id: Id1d264ade3799f431bf7ebbdcca6146aefbeb632