Grant getpgid to system_server on zygote

Should system_server kill zygote on crashes, it will attempt to kill any
process in the same process group. This ensures that no untracked
children are left.

Bug: 216097542
Test: m selinux_policy
Change-Id: Ie16074f76e351d80d9f17be930a731f923f99835
(cherry picked from commit 6390b3f09066bc258e0dc09c73aaaf778239169b)
Ignore-AOSP-First: backport with update to prebuilts
2 files changed