Add sampling profiler

This adds a sampling profiler thread that runs every so often, gathering
profiling data and writing the results to a file in /data/data (specific to
app running).  The intention is to use these files as input to the compiler
so that it can determine the best methods to compile.

Bug: 11539952
Change-Id: I0bfbb4146fb7966673c792f017ffac8107b6272d
14 files changed