simpleperf: Move code handling ETMBranchList file to a separate file

So it can be shared between the inject cmd and the record cmd.

Bug: 279094308
Test: run simpleperf_unit_test
(cherry picked from https://android-review.googlesource.com/q/commit:f5ff15d246250c707fc612c586190679f3fe7c6f)

Merged-In: I5865c885f32e812e43a4ee8f30beea72dffc3f72
Change-Id: I5865c885f32e812e43a4ee8f30beea72dffc3f72
9 files changed