Shader -> SPIR-V at CTS build time (#1849) (#1878)

* Shader -> SPIR-V at CTS build time (#1849)

Instead of relying on prebuilt checked-in SPIR-V files, compile
available shaders at CTS build time.

* Add dependency on glslc (available as part of VULKAN_SDK).
* Add optional build flag BUILD_GLSL_SHADERS, OFF by default.

* Remove pre-built SPIR-V files

* Compile Shader -> SPIR-V at CTS build time

* Use glslangValidator for shader -> spirv

* Add glslangValidator tool for shader -> spirv

* Refactor glslangValidator tool retrieval

* Address review comments

* Use add_subdirectory() instead of include()
* Use glslang instead of glslangValidator
* Update Github actions CI to install Vulkan SDK

.github/workflows/presubmit.yml

@@ -50,6 +50,11 @@ jobs:
           cd OpenCL-Headers
           ln -s CL OpenCL # For OSX builds
           cd ..
+      - name: Install Vulkan SDK
+        uses: humbletim/install-vulkan-sdk@main
+        with:
+          version: 1.3.275.0
+          cache: true
       - name: Build
         shell: bash
         run: ./presubmit.sh