Fix CHECK for homogenous space compaction

Fix CMS from erroring out when background_collector_type_ is
gc::kCollectorTypeHomogeneousSpaceCompact. This GC type is a "moving"
GC.

Fixes test breakages.

Test: make

Change-Id: Idc949fecd51443c0f924e7554f1098b758e808f2
1 file changed