Inclusive language fixes in ART's garbage collector.

Update language to comply with Android’s inclusive language guidance.
See https://source.android.com/setup/contribute/respectful-code for
reference.

#inclusivefixit

Test: Build ART and run ART tests
Bug: 161336379
Bug: 161896447
Change-Id: Ib4aef98db2a9fd1031a076af0eab3fcb4cf6afef
8 files changed