Remove vestigial LLVM_jll from the test environment

[maleadt]

Problem

All Julia nightly CI jobs have failed since 2026-06-29. Julia 1.14 nightly (JuliaLang/julia#61709) rejects cglobal calls whose library-name element is a computed expression, enforced at method-definition time — so merely include-ing such a file throws:

TypeError: in cglobal library name, expected Symbol, got a value of type Expr

test/Project.toml pinned LLVM_jll = "15,16,18,20". On nightly that capped LLVM_jll at v20.1.8+0, whose platform_augmentation.jl contains exactly such a call:

cglobal((:_ZN4llvm24DisableABIBreakingChecksE, Base.libllvm_path()), Cvoid)

Pkg.test → instantiate → download_artifacts runs each augmented JLL's select_artifacts.jl in a subprocess; including that file now throws and kills the whole Pkg.test.

Fix

GPUCompiler's tests never use LLVM_jll directly — they use FileCheck.jl's @filecheck/@check_* macros. FileCheck.jl itself depends on LLVM_jll and locates the FileCheck binary via its artifact (joinpath(LLVM_jll.artifact_dir, "tools", "FileCheck")). So the explicit LLVM_jll entry in the test deps was vestigial; its only effect was the version bound, and that bound is what pinned the broken v20.1.8+0 build on nightly.

Dropping the dep lets FileCheck.jl govern resolution:

• Julia 1.14: FileCheck v1.2.0 (which no longer bounds LLVM_jll) resolves the fixed LLVM_jll v21.1.8+1, whose augmentation uses Libdl.dlsym(dlopen(...)) (JuliaPackaging/Yggdrasil#13664).
• Older Julia (1.10–1.13): unaffected — julia-compat keeps LLVM_jll at ≤ v20, and those Julia versions accept the dynamic cglobal.

Verification

Full suite on nightly (1.14.0-DEV), with LLVM_jll removed from the test deps: resolves FileCheck v1.2.0 + LLVM_jll v21.1.8+1, FileCheck binary found, 336 pass, 3 broken. No cglobal instantiate error.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.02%. Comparing base (c740f2e) to head (b589a67).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #867      +/-   ##
==========================================
+ Coverage   79.60%   80.02%   +0.41%     
==========================================
  Files          25       25              
  Lines        4805     4805              
==========================================
+ Hits         3825     3845      +20     
+ Misses        980      960      -20     

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