CFI: Enable stack traces in renderer process in non-official CFI builds.

A CFI failure causes a SIGILL signal to be raised, and the most likely
place for a failure to occur is in the renderer. By printing a stack trace
we provide developers with a basic set of information about CFI failures,
and allow crashes to be disambiguated by ClusterFuzz.

BUG=464797
R=jln@chromium.org,jam@chromium.org

Review URL: https://codereview.chromium.org/1269673003

Cr-Commit-Position: refs/heads/master@{#341833}
2 files changed