Merge "Convert firstword/lastword to starlark functions instead of index...

Merge "Convert firstword/lastword to starlark functions instead of index operators" am: 7940585c am: 312fda06 am: a6babb77 am: ccaccce6

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



Change-Id: I7dd2ecc268758f9269b7bcd6475fb4559b927284
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>