ART: add dump region info runtime option

Introduce two new runtime options, DumpRegionInfoBeforeGC and
DumpRegionInfoAfterGC, for printing the live bytes ratio for non-free
regions before and after each GC cycle.

Test: Run art with -XX:DumpRegionInfoBeforeGC and -XX:DumpRegionInfoAfterGC on some benchmarks.
Bug: 119486919
Change-Id: I0d6f210669b85d94034178815f6cae6fd19ca397
7 files changed