IA2: Separate do_in_main_thread into library am: d449017e am: 61d2dfdb am:...

IA2: Separate do_in_main_thread into library am: d449017e am: 61d2dfdb am: ac37e10f am: 773232ed

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Bluetooth/+/2761128



Change-Id: I5b10298f0cd8673a037a7e6151b84091509bdaae
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>