Revert "Disable AOSP prebuilt APEX for ART." The AOSP prebuilt APEX need to remain enabled to provide dex jars to prebuilt SDKs in branches where the internal APEX in vendor/unbundled_google/modules/ArtGooglePrebuilt/ isn't available. This reverts change-id If66a8938336ff0aaa103b6fe92d53c7628e72e5d. Bug: 192455918 Bug: 172480615 Change-Id: If28e89153e5fa5bd17c0f2c1415cd17897e6443c Merged-In: If28e89153e5fa5bd17c0f2c1415cd17897e6443c (cherry picked from commit 89d4f1a8c87599632184a0e9147d993e54dfe695)