Merge "Copy the out/soong/build_number.txt file into sdk snapshots" am:...

Merge "Copy the out/soong/build_number.txt file into sdk snapshots" am: d72c8521 am: 1a8ec421 am: 66459a51

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/2056132



Change-Id: I3792b60c8f39d9aec2900d5f19cab9e74ba6864b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>