Two functions we call in signal handlers call malloc() down the line.
Because these functions generally happen while the thread was dying, we
will permit the AS-unsafe call, especially since we've never had any
problems with any allocators we've ever used.
WiredTiger is known to cause false positives for data races because it
uses a nonstandard thread model that TSAN doesn't know how to deal with.
We have already blacklisted WiredTiger in TSAN, but that only affects
threads created within the WiredTiger source. For threads that call
*into* WiredTiger, we need to add suppressions so we still get any
potential failures from elsewhere.
Fix death tests running under ThreadSanitizer. Death tests were causing
TSAN to emit a signal report, which is a false positive. The signal
report was then causing the expected failure message to not be parsed as
JSON. TSAN ignal reports will be suppressed for all death tests.
