Specifically, make Android.bp.list and soong.variables explicit inputs
While this is not a comprehensive list of all inputs
of this action (as the action depends on all blueprint
files in the source tree), this is closer to the truth.
This is a rollforward CL, which was originally rolled
back, as path validation failed for when OUT_DIR was
an absolute path. Validation has now been relaxed.
Test: Manually verified ninja output, checkbuild approved validation
for aosp-crosshatch, and manually ran frameworks/rs/build_rs.py with
patch fix
Change-Id: I4eb0d517f57336dd54eaa4bd31f46df9e93e6da2
8f232a2702