Add get initial regs to ThreadUnwinder. am: 875fd55938

Original change: https://android-review.googlesource.com/c/platform/system/unwinding/+/1981166

Change-Id: Ic47772da5559dacd67874608ae95bcc3fd2fd350
tree: 7b74d3c42065befea88a997e23e37b941d974ff3
  1. libbacktrace/
  2. libunwindstack/
  3. OWNERS
  4. PREUPLOAD.cfg