Upgrade libkmsxx to b12aab5d4bb45e77934d9838576a817bc8defe4b am: a520d8d4be

Original change: https://android-review.googlesource.com/c/platform/external/libkmsxx/+/1541424

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I4464b1e79aaa9464aa75c6c5386ceb00fc3a1221