Add timestamps to JIT/DEX native debug info.

This a forward-looking change intended to allow simpleperf to
reliably correlate samples and native debug information.

I have added the timestamps to both JIT and DEX, and refactored
the code in the process to avoid code duplication.

Test: testrunner.py -t 137
Change-Id: I45fa4310305aff540e036db9af15a86c5b8b7aff
11 files changed