Simpleperf: do dwarf unwinding in record command.

As libbacktrace only supports unwinding for the same architecture it is running on, simpleperf
report command running on host can't unwind perf.data collected on device. So we'd better do
unwinding work in record command on device.

Bug: 22229391
Change-Id: I085ca074ea83dab79f08563523bdbc7a36650a64
6 files changed