[CI][C++][Release] Flaky libLLVM load failure in macOS verify-rc build

[tadeja]

Describe the bug, including details regarding any error messages, version, and platform.

The nightly job Verify release candidate on macOS intermittently aborts the C++ build:

dyld[24719]: Library not loaded: @rpath/libLLVM.22.1.dylib
  Referenced from: .../miniforge/pkgs/llvm-tools-22-22.1.8-hc181bea_1/bin/llvm-ranlib-22

Conda's LLVM tools resolve libLLVM via @loader_path/../lib and can point at the package cache which has no libLLVM.
Not caused by LLVM 22.1.8 (initial incorrect assessment). The same packages 22.1.8 pass in other runs.

There are two such failing jobs:

• https://github.com/ursacomputing/crossbow/actions/runs/27960474749/job/82740300712 (mimalloc)
• https://github.com/ursacomputing/crossbow/actions/runs/27960469209/job/82740279170 (Gandiva)

Component(s)

C++, Continuous Integration

[kou]

Is this a problem of the LLVM conda package? If so, we need to report this to the LLVM conda package.