simpleperf: fix dumping build id.

1. Dump build id for binaries hit by callchain ips.
2. Fix a memory used after free bug in ReadBuildIdFeature().

Bug: http://b/32340274
Test: simpleperf_unit_test.
Test: check output of `simpleperf dump` manually.
Change-Id: I0132e5ce0e06096413231325e9f1d215143eedd2
2 files changed