Update the tests.

- Change all load_base to load_bias in the test files.
- Add the test files to the backtrace_test.
- Add a function to get the path to the test libraries.
- Change aarch64 to arm64 for offline test code.
- Modify the offline tests so that they can be easily updated when
  unwinding on any arch for any other arch is possible.
- Add tests of CreateNew for remote debugging.

Test: Ran unit tests on host and angler.
Change-Id: Id6c5afe73aeb2ac22463dd81f061799fcb1c178b