Revert "rusty-gd: move init_flag parsing to rust"

Revert submission 1512686

Reason for revert: DroidMonitor-triggered revert due to breakage https://android-build.googleplex.com/builds/quarterdeck?branch=aosp-master&target=mainline_modules&lkgb=7010703&lkbb=7011903&fkbb=7010786, bug b/174815635
Bug: 174815635
Reverted Changes:
I163111bc8:rusty-gd: move init_flag parsing to rust
I54cffe93d:rusty-gd: compile into libbluetooth
I5207f4df9:rusty-gd: add stack start stubs, define shim libra...

Change-Id: I5740575cf7790ed1ab43cc3f521e86f4ef6966e6