Use ParallelTestRunner.jl for parallel test execution
- Rewrite test/runtests.jl to use ParallelTestRunner: auto-discovery
via find_tests, env-flag-based filtering, and init_code that loads
test_module.jl in every worker subprocess
- Rename test/test_utils.jl → test/test_module.jl; add imports,
conditional optional-package loading via Base.find_package, and
include ext_reactant/test_utils_reactant.jl when Reactant is present
- Add ParallelTestRunner and Reactant to test/Project.toml
- Append normalization_testsuite(cpu) call to layers/normalisation.jl
(replaces the old flux_testsuite(cpu) call in runtests.jl)
- Update AGENTS.md with new test invocation commands
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
