[automerger skipped] Revert "Create exported mode flag library for package android.os"" am: a60282b274 -s ours

am skip reason: Merged-In I445d8e8fecc1fead739847c756cfba66a384c978 with SHA-1 d447c13793 is already in history. Merged-In was found from reverted change.

Reverted change: https://android-review.googlesource.com/c/platform/frameworks/base/+/3165262

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/3166659

Change-Id: Ia376a45b60aeee461c4777f0a399df5bd7ae16ff
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>