Handle additional record types in perf.data reader.

Enhance the perf.data reader in perfprofd to handle the new kernel
symbol records that simpleperf generates. In addition, add support for
handling PERF_SAMPLE_REGS_USER and PERF_SAMPLE_STACK_USER records as
well (these wind up in perf.data files if callchain profiling is
used). Perfprofd doesn't need to look at any of the data in these
records, but it does need to be able to read past them.

Bug: 29067424
Bug: 29067428
Change-Id: I38c12f6a219a4d28afe50e0418d30cfdcd1a9222
9 files changed