Merge "Convert firstword/lastword to starlark functions instead of index operators" am: 7940585c

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/2078798



Change-Id: If241540a21eeec6abe3693f21431844ca9db3cb9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>