Revert "core: Move core.oat bootjar definitions into core/config"

This reverts commit 8c507982.

Possible culprit of breakage in git_master sdk_google_aw_x86:
FAILED: out/target/product/generic_x86/dex_bootjars/system/framework/x86/boot.art 
ex2oatd E 06-15 03:56:00 47990 47990 runtime.cc:1761] Failed to return pre-allocated NoClassDefFoundError
dex2oatd F 06-15 03:56:00 47990 47990 thread.cc:3591] Check failed: new_exception != nullptr 

Testing if Treehugger passes with the rollback before submitting

https://android-build.googleplex.com/builds/submitted/4101897/sdk_google_aw_x86-sdk/latest/view/logs/build_error.log

Change-Id: Iceac31e775eaf3cd5fd9b3d2a17d3af200e35b27