Add SPIR-V language with SPIRV-Tools compilers (#6947)

for https://github.com/compiler-explorer/compiler-explorer/issues/2331

Hey, so I am currently trying to improve the SPIR-V ecosystem, in-charge
of the [SPIR-V Guide](https://github.com/KhronosGroup/SPIRV-Guide), and
part of the SPIR-V Working Group. We talked at our last Face-2-Face
gathering about getting more support for GPU tooling in something like
Compiler Explorer because you have all made this such an amazing tool!

I have enjoyed working in this codebase and happy to help keep improving
the SPIR-V as people find issues or want enhancements (I was already
about to spend time rebuilding Compiler Explorer, so happy to donate my
time to a single tool's effort)

(For those who haven't spent last few years staring at SPIR-V)

- SPIR-V is a an IR (very much like LLVM IR) but for GPUs
- SPIR-V can be used for Graphics and Compute
- Compute:
    - Can be tied to things like clang, llvm, mlir, OpenCL, etc
- One could take `spirv` as a language and compile it to something like
x86
      - (Future PRs for this realm of things)
- Graphics:
- Much harder to actually "compile" to any ISA because other graphics
pipeline information is missing that will effect the final ISA
- Microsoft has even now planned to move to [SPIR-V for DirectX
soon](https://devblogs.microsoft.com/directx/directx-adopting-spir-v/)
- Both:
- There are many tools that run on SPIR-V regardless (hence why they
share the same IR)
    - Being able to do tooling in compiler explorer would be AMAZING

This PR adds `SPIR-V` as a language and a new `SPIRV-Tools` compiler as
an initial compiler for it the language (since we already have the
SPIRV-Tools repo being pulled in on the infra side!)

I personally use `spirv-opt` and `spirv-val` the most and have been
testing this locally for a few days and feel it is ready to go. I plan
to slowly add more tools (ex. `spirv-fuzz`, `spirv-cross`,
`spirv-reflect`, etc)

Cheers!

(some screenshots of course)

![image](https://github.com/user-attachments/assets/419feab0-d030-4578-b32a-ef1cf95701da)

![image](https://github.com/user-attachments/assets/a00fa60f-7f05-4522-a9fc-1c43ecee1c42)

.github/labeler.yml

@@ -340,6 +340,14 @@
           - 'etc/config/spice.*.properties'
           - 'static/modes/spice-mode.ts'
 
+'lang-spirv':
+  - changed-files:
+      - any-glob-to-any-file:
+          - 'lib/compilers/spirv.ts'
+          - 'lib/compilers/spirv-tools.ts'
+          - 'etc/config/spirv.*.properties'
+          - 'static/modes/spirv-mode.ts'
+
 'lang-swift':
   - changed-files:
       - any-glob-to-any-file: