Share Caches' index buffer with FontRenderer

This reduces state changes when we draw 9patches and text together,
which happens *a lot*. Also disable the NV profiling extension by
default since it doesn't play nice with display lists deferrals.
To enable it set debug.hwui.nv_profiling to true.

Change-Id: I518b44b7d294e5def10c78911ceb9f01ae401609