ART: Add dump-on-timeout helper

Add a remote-backtrace util that activates on a timeout signal.
Approach mostly derived from old debuggerd code, and tested by
manually lowering the default timeout.

Test: mmma art
Test: m test-art-host
Change-Id: I2c8c3426e5b1ed646d93cc8babeacaf5283a360d
4 files changed