Vulkan: Very rough first implementation of compute shaders

Vulkan: Very rough first implementation of compute shaders

This is by no means finished:
* ComputeProgram holds the codegen and the invoke logic. ComputeProgram::run() should probably be moved somewhere else (maybe Renderer?).
* ComputeProgram::run() is currently fully single threaded.
* The compute routines are currently not cached.

With that said, this is enough to start passing a whole bunch of dEQP compute tests.

Test: *.compute.*
Bug: b/126871859
Change-Id: Ic6a76826b2fec0d34d54e0bed564b360ea0610c0
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/26551
Presubmit-Ready: Ben Clayton <bclayton@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>