simpleperf: Use ETMThreadTree interface in ETMDecoder

So it's easier to modify the behavior of thread tree used in ETMDecoder.

Also disable thread exit records when decoding ETM data.

Bug: 279094308
Test: run simpleperf_unit_test
(cherry picked from https://android-review.googlesource.com/q/commit:2b1cfec062726c3a5ebf07110cb43ef7b5144ca2)

Merged-In: Ie40192219929043bd8675101411bc38870106746
Change-Id: Ie40192219929043bd8675101411bc38870106746
6 files changed