simpleperf: support "--app" option in record/stat command.

simpleperf: support "--app" option in record/stat command.

By using --app [package_name] option, users don't need to
manually run run-as or look for the app's process.
It is also good for profiling app startup time.

For simpleperf, it now can start in the shell's context,
and be able to get tracing events information, which can
support profiling tracepoint events for apps. This is
useful for monitoring thread sleep time.

This CL is tested manually, but I will change the
way of running simpleperf cts test to test this.

Bug: http://b/34108866
Test: test manually.

Change-Id: I8db0390af8e49c56dc4860374153f753bbcf9b11