debuggerd: update policy for recent sigaction changes.

Commit 3e235911 in bionic switched LP32's sigaction implementation over
to using the rt_sigaction syscall, matching LP64. Update our seccomp
policy to match.

Bug: http://b/73119572
Test: debuggerd_test32
Change-Id: I0a662a1c874298d434468d2dcdb4ebf9f276110c
5 files changed