[metrics] Dump ArtMetrics on SIGQUIT
ART now writes a current snapshot of its internal metrics in response to
a SIGQUIT.
Example output:
```
*** ART internal metrics ***
ClassVerificationTotalTime: count = 863833
JitMethodCompileTime: range = 0...1000000, buckets: 244,5,1,0,1,0,0,0,0,1,0,0,0,0,0
*** Done dumping ART internal metrics ***
```
This includes a new StreamBackend, which is used to write ART metrics to
an output stream in a human readable format.
Bug: 170149255
Test: m test-art-host-gtest-art_libartbase_tests
Change-Id: Iaf8bcee5a4993e70ac4e36940591a734fe1a6697
4 files changed