Move the mainline SDK definition to system/libartpalette. am: 724d27147f am: 7cabb20ff5 am: e2abb2aacb am: 2b8bb10917

Original change: https://android-review.googlesource.com/c/platform/system/libartpalette/+/1382579

Change-Id: Ib3f0124afee72bcda7821f8fd51b9bf826087762