[llvm] [SPIR-V] Add SPIRV to LLVM_ALL_TARGETS (PR #119653)

[Jakub Kuderski via llvm-commits]

================
@@ -47,6 +47,12 @@ for adding a new subsection. -->
   same semantics. The normalizer makes it easier to spot semantic differences
   when diffing two modules which have undergone different passes.
 
+* The SPIR-V backend is now an official LLVM target, enabling support for 
+  SPIR-V across a range of APIs and use cases, including OpenCL, Vulkan, SYCL,
+  GLSL, and HLSL. This backend serves as a unified solution for diverse compute
+  and graphics workloads, offering a robust alternative to the Khronos SPIR-V
----------------
kuhar wrote:

How robust is the Vulkan support as of today? I understand that for opencl you track the pass rate on the CTS (https://discourse.llvm.org/t/rfc-promoting-spir-v-to-an-official-target/83614), but I wonder if we can quantify how robust the support if for other subtargets and whether we should add a disclaimer here.

https://github.com/llvm/llvm-project/pull/119653