debuggerd: fix CrasherTest.seccomp_crash_oom.

Switch from _exit to raising SIGABRT when we recurse in the fallback
handler, so that waiters see an abort instead of a regular exit.

Bug: http://b/79717060
Test: debuggerd_test32
Test: debuggerd_test64
Change-Id: Iddee1cb1b759690adf07bbb8cd0fda2faac87571
1 file changed