Implement copying between a buffer and a texture 2D array on Vulkan
This patch implements the creation of a 2D array texture and data
copying between a buffer and a layer of a 2D array texture on
Vulkan back-ends.
TEST=dawn_end2end_tests
We still keep a dummy BufferBuilder object around so that it can be used
for the builder error callback tests of the wire.
Change-Id: If0c502bb8b62ee3ed61815e34e9b6ee6c03a65ef
Also moves the TerribleCommandBuffer to utils:: because it isn't part of
the implementation of the wire, renames dawn::wire to dawn_wire, moves
src/wire to src/dawn_wire and puts the interface of dawn_wire in
src/include/dawn_wire.
