Merge "aconfig_storage: create aconfig storage c++ flag value write api" into main am: aa028764

Original change: https://android-review.googlesource.com/c/platform/build/+/3004210



Change-Id: I3623a3b836ee8d09c759885e759b9f2eafe8a7dc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>