Auto merge of #23407 - georgeroman:reintroduce_parallelism_in_bluetooth_tests, r=jdm

Reintroduce parallelism in the bluetooth tests

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With https://github.com/web-platform-tests/wpt/pull/16819 in place, https://github.com/servo/servo/issues/22619 should be fixed, so the changes introduced by https://github.com/servo/servo/pull/22662 can be reverted.

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors

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etc/taskcluster/decision_task.py

@@ -573,7 +573,7 @@ def wpt_chunks(platform, make_chunk_task, build_task, total_chunks, processes,
                     tests/wpt/mozilla/tests/css/img_simple.html \
                     tests/wpt/mozilla/tests/mozilla/secure.https.html \
                     | cat
-                time ./mach test-wpt --release --processes 1 --product=servodriver \
+                time ./mach test-wpt --release --processes $PROCESSES --product=servodriver \
                     --headless --log-raw test-bluetooth.log \
                     --log-errorsummary bluetooth-errorsummary.log \
                     bluetooth \