Translate --custom-package aapt2 flag for ResourceProcessorBusyBox

When --custom-package is specified as an aapt2 flag translate it to
--packageForR when running ResourceProcessorBusyBox.

Bug: 294256649
Test: m javac-check
Change-Id: I2c97c760ea8a0203790feda82b98e12c2dbd7b72