Add missing syscalls to mediaextractor arm64 seccomp filter

Two missing calls were preventing debuggerd from catching crashes
in mediaextractor

Test: triggered crash and verified debuggerd catches it

Change-Id: I3306207bff9af1fd63ad66761bc650d6f5147d98
diff --git a/services/mediaextractor/minijail/seccomp_policy/mediaextractor-seccomp-arm64.policy b/services/mediaextractor/minijail/seccomp_policy/mediaextractor-seccomp-arm64.policy
index ae6ac05..7e7b858 100644
--- a/services/mediaextractor/minijail/seccomp_policy/mediaextractor-seccomp-arm64.policy
+++ b/services/mediaextractor/minijail/seccomp_policy/mediaextractor-seccomp-arm64.policy
@@ -28,6 +28,8 @@
 getrlimit: 1
 
 # for attaching to debuggerd on process crash
+tgkill: 1
+rt_sigprocmask: 1
 rt_sigaction: 1
 # socket: arg0 == AF_LOCAL
 socket: arg0 == 1