Don't hide error by INVALID_MAP in speculative frame.

When an unwinding step fails, unwinder tries return address.
And if the return address hits INVALID_MAP error, it will hide
the error of the previous unwinding step.

Bug: 215556268
Test: run libunwindstack_unit_test
Change-Id: I4acbb3389cc075396cde213fbf3cdeac64659f6a
2 files changed
tree: f32c2d508c283ce6e9b3f1230887346e473a83b8
  1. libbacktrace/
  2. libunwindstack/
  3. OWNERS
  4. PREUPLOAD.cfg