Fully remove forced concurrency on macOS

One at a time is better than thrashing

Author: christiangnrd

.github/workflows/Test.yml

@@ -42,11 +42,6 @@ jobs:
         run: |
           # Run tests in verbose mode
           TEST_ARGS=(--verbose)
-          # if [[ ${{ runner.os }} == "macOS" ]]; then
-          #     # Encourage ParallelTestRunner to use two jobs on macOS, rather
-          #     # than the single one it'd use by default.
-          #     TEST_ARGS+=(--jobs=2)
-          # fi
           echo "runtest_test_args=${TEST_ARGS[@]}" >> "${GITHUB_ENV}"
       - uses: julia-actions/julia-runtest@v1
         continue-on-error: ${{ matrix.version == 'nightly' }}