Merge "Factor out shared variant options from config when writing." into main am: 0b2d7be56b

Original change: https://android-review.googlesource.com/c/platform/development/+/2822473

Change-Id: If872263f3b9d05f2e45e87c827f3f0f6453db109
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>