OpenCL/Vulkan: Add initial program build support Introducing both clspv compiler lib integration, and clBuildProgram support. Internally we also add buildInternal() routine to abstract compile, link, and build phases. Output SPIR-V is also parsed internally via parseReflection() so that we can extract needed reflection information for CL runtime. Bug: angleproject:8549 Change-Id: If0563f4bea7ed0e04a13ea7a46c125c811d9c2a2 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5303564 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>