Report all toolchain JLLs and their overrides in versioninfo

[maleadt]

OpenCL.versioninfo() now also lists SPIRV_Tools_jll and spirv2clc_jll, and says when a JLL's products don't come from the registered artifact. That covers both override mechanisms: a <product>_path preference (e.g. libpocl_path, which this repo's CI uses to test PoCL HEAD) and an Overrides.toml entry for the artifact. This makes the test logs (runtests.jl prints versioninfo) show which binaries were actually used.

I need this for spirv2clc's CI (JuliaGPU/spirv2clc#2), which runs this package's poclc/ tests with spirv2clc_jll pointed at the binary under test. Example local output, with a spirv2clc_path preference on top of an Overrides.toml entry, and a libpocl_path preference:

Toolchain:
 - Julia v1.13.0
 - OpenCL: 2024.10.24+1
 - SPIRV_LLVM_Backend: 23.1.1+1
 - SPIRV_Tools: 2025.4.0+0
 - spirv2clc: 0.2.0+4 (overridden: artifact = /home/tim/Julia/src/spirv2clc/build, spirv2clc = /var/tmp/.../spirv2clc-prefix/bin/spirv2clc)
...
- pocl_jll: 7.2.0+1 (overridden: libpocl = /home/tim/Julia/src/pocl/target/lib/libpocl.so)

Without overrides the output is unchanged apart from the two added JLLs.

[codecov]

Codecov Report

❌ Patch coverage is 94.73684% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 83.34%. Comparing base (109e340) to head (a2f0d5b).

Files with missing lines	Patch %	Lines
src/util.jl	94.73%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #507      +/-   ##
==========================================
+ Coverage   83.23%   83.34%   +0.10%     
==========================================
  Files          19       19              
  Lines        1587     1603      +16     
==========================================
+ Hits         1321     1336      +15     
- Misses        266      267       +1     

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