Don't pass --profile to nextest run (#377)

It means something different in nextest

.github/workflows/tests.yml

@@ -160,9 +160,9 @@ jobs:
           install cargo-mutants ~/.cargo/bin/
       - name: Mutants in-diff
         # Normally this would have --in-place, but for the sake of exercising more cases, it does not.
+        # TODO: Pass --profile=mutants when supported
         run: >
           cargo mutants --no-shuffle -vV --in-diff git.diff --test-tool=${{matrix.test_tool}} --timeout=500 --build-timeout=500
-          --cargo-arg=--profile=mutants
       - name: Archive mutants.out
         uses: actions/upload-artifact@v4
         if: always()