Merge "Drop supplementary groups for child zygotes." into rvc-dev am:...

Merge "Drop supplementary groups for child zygotes." into rvc-dev am: 1a081317 am: 0a5d18b0 am: 25a4aa7f

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11691823

Change-Id: I44f5072b20a61f650af4f907a3e6da974917291b