Support to use kallsyms

Also:
- Adapt to use with Python 3
  (where str is a wide type but our C API's expect 8 bit character strings)
- Use OS specific so names (e.g. simpleperf_report.dll on Windows)
- On Windows as we use mingw to build, preload libwinpthread-1.dll.

Test: with manual incovation using report_sample.py
Change-Id: Id973c463608c520b8eec229026c74dc5e8144cf8
8 files changed