simpleperf: Remove small stack gaps in the report-sample command

Similar to gecko_profile_generator.py (in aosp/2457550), we remove
small stack gaps in the report_sample command, to improve Stack Chart
View in Android Studio Profiler.

By default, we remove stack gaps with length <= 3. But this can be
controlled by --remove-gaps. For example, we can stop removing gaps
by using `--remove-gaps 0`.

Bug: 270628163
Test: run simpleperf_unit_test
Change-Id: Ib7e177cec234f2a98aff4e069a2d30256d988ba3
2 files changed