Revert^2 "Add the mainline framework boot image extension to the default." am: 43f9a4abb8 am: ca4164de75 am: 5ca25fb89d

Original change: https://android-review.googlesource.com/c/platform/art/+/2458432

Change-Id: Iffb65f7b26717f45e0b0833476f5b680c13c7a0b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>