Add new product aosp_arm_ab

The product is for GSI with ARM 32-bits and A/B update.

Bug: 38339485
Test: Build pass
Change-Id: Ifad208d2e625f30d0a3dd964d53d81257eeefabf
Merged-In: Ifad208d2e625f30d0a3dd964d53d81257eeefabf
(cherry picked from commit fbc4835f)