[metrics] Move metrics code to runtime

The background reporting thread is going to need tighter ties to the
Runtime object, so it makes sense to bring the rest of the metrics code
under runtime. Since these are mostly runtime metrics, this is a more
logical place for them anyway.

Test: m test-art-host-gtest-art_runtime_tests
Bug: 170149255
Change-Id: Ib425041c41a5283237af8dd9978582e605a89a31
8 files changed