Auto merge of #25451 - kunalmohan:19308-AccountableRefCell, r=jdm

Add accountable-refcell as optional build time feature

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It can be used with the format `./mach build --features refcell_backtrace`.

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<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #19308  (GitHub issue number if applicable)

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- [X] These changes do not require tests because it adds a optional build-time feature only.

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etc/taskcluster/decision_task.py

@@ -206,7 +206,7 @@ def linux_tidy_unit():
             python3 ./mach build --dev
             python3 ./mach test-unit
             python3 ./mach package --dev
-            python3 ./mach build --dev --features canvas2d-raqote
+            python3 ./mach build --dev --features refcell_backtrace
             python3 ./mach build --dev --features layout-2020
             python3 ./mach build --dev --libsimpleservo
             python3 ./mach build --dev -p servo-gst-plugin