Revert "track master sytem/core"

This reverts commit 4e12cb398c08751f55c5bf76172e5c44443722c2.
Revert "track modified android_build with master patches for master updates"

This reverts commit 87ea98fa2d9325fac87bddbe4213c2a7f0c5b76d.
Revert "switch art, bionic, dalvik, skia to MASTER"

This reverts commit 2416fdb5fd405574c7a397430e2ad44408433522.

Conflicts:
	default.xml

Change-Id: Ia958ccf2b929b56fc1621ff4c22dff2bddc85141