[9.18] chg: nil: Suppress FreeBSD-specific TSAN false-positive lock-order-inversion

TSAN reports a lock-order-inversion (potential deadlock) issue in
add_trace_entry().

While it is true that in one case a lock in the 'isc_mem_t' structure is
locked first, and then a lock in the 'FILE' structure is locked second,
and in the the second case it is the other way around, this isn't an
issue, because those are 'FILE' structures for totally different files,
used in different parts of the code.

Closes #5266

Backport of MR !10355

Merge branch 'backport-5266-freebsd-suppress-tsan-lock-order-inversion-false-positive-9.18' into 'bind-9.18'

See merge request isc-projects/bind9!10371