Generalize abort's inline_tgkill, use it in fdsan.

Convert abort's inline_tgkill to do the equivalent of
pthread_sigqueue(pthread_self(), ...), so that we can use it in fdsan
as well.

Test: bionic-unit-tests
Test: debuggerd_test32
Test: debuggerd_test64
Change-Id: I92a7b84e2f00ce021b4043ed8a3bd8683d77fe9c