Perfprofd: Implement simpleperf interrupt

Change profiling to wait for the requested duration. This allows
profiling to be interrupted when simpleperf is already running.

When profiling should be stopped, send a SIGHUP to simpleperf, which
will make it finish sampling and clean up.

Test: m
Change-Id: I1572afcf61dd89bfaee00b036e4301e86e66e993
1 file changed