simpleperf: add META_INFO feature section in perf.data.

META_INFO section can be used to pass some small information
in perf.data.

Add simpleperf_version in META_INFO section for debugging.

Bug: http://b/37960318
Test: run simpleperf_unit_test.
Change-Id: If17a147bbc77b5af063fbf77e02ca81430afb8a5
11 files changed