Set report_signal_unsafe=0 on TSAN bots.

We don't really care about report_signal_unsafe.
Our signal handlers all just dump out a stack trace and crash.
If they crash themselves due to signal unsafe code, no big deal.
(I've never seen that happen.)

Change-Id: Ibb90b2b323d88a56d64e6ea62b9c0924a4e41444
Reviewed-on: https://skia-review.googlesource.com/50120
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
4 files changed