dvm: Bring back the ANDROID_DATA override

This got broken by the split-cache patch, and it's impacting the
CTS vm unit. Fixit.

Change-Id: I602824afef19c92a4d2c1702d10c8f0315277227

Conflicts:
	libdex/OptInvocation.cpp
debug: allow ability to hide GC freed lines in logcat

use setprop dalvik.vm.debug.alloc 0 to disable these noisy logs...

Change-Id: I8692b941901b43d33ea9ee30c288a47b6a3be3b1