Fix TSAN signal interceptor out-of-bound access

signal(2) and sigaction(2) have defined behaviors for invalid signal number
(EINVAL) and some programs rely on it.

The added test case also reveals that MSAN is too strict in this regard.

Test case passed on x86_64 Linux and AArch64 Linux.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D106468