Merge "Add ability to say a custom partition doesn't want to participate in...

Merge "Add ability to say a custom partition doesn't want to participate in fastboot flashall" into main am: d8ac6c96 am: 16a0b229

Original change: https://android-review.googlesource.com/c/platform/build/+/3518233



Change-Id: I7ba92e4f7a05577402aa166b7fbfb63ef965d4fe
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>