Add VLOG(collector) to reduce log spam

VLOG(gc) is enabled from AndroidRuntime, using it too much produces
log spam.

Bug: 22858531

(cherry picked from commit a6e1c126299586932ecd3c1133a55a6f8e1107fc)

Change-Id: If60902a8d7855cdabd80208b9b385ce4ba4d9e5f
5 files changed