We had been looking in lib.stripped for the library when symbolizing
debuggerd traces. The libraries in lib.stripped are not the ones with
packed relocations, though, so the resulting symbolization was wrong.

This CL generates a wrapper script around the stack symbolization
script that points to the correct library to use for symbolization.
It also contains a few tests that intentionally crash in various ways.
These are all disabled by default and should only ever be run manually
for testing out instrumentation test crash tooling.

BUG=712265

Review-Url: https://codereview.chromium.org/2840193003
Cr-Commit-Position: refs/heads/master@{#468206}