Auto merge of #14025 - iamrohit7:debug-assertions, r=Wafflespeanut

Add --with-debug-assertions flag for Mach

I tested out building a release with the flag and added a `debug_assert!(false)` in `fn main` and it panicked.
<!-- 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 #14009  (github issue number if applicable).

<!-- Either: -->
- [ ] There are tests for these changes OR
- [X] These changes do not require tests because they are manually tested

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etc/ci/buildbot_steps.yml

@@ -55,15 +55,15 @@ linux-dev:
   - bash ./etc/ci/check_no_panic.sh
 
 linux-rel-wpt:
-  - ./mach build --release
+  - ./mach build --release --with-debug-assertions
   - ./mach test-wpt-failure
   - ./mach test-wpt --release --processes 24 --log-raw test-wpt.log --log-errorsummary wpt-errorsummary.log
   - ./mach test-wpt --release --binary-arg=--multiprocess --processes 24 --log-raw test-wpt-mp.log --log-errorsummary wpt-mp-errorsummary.log eventsource
 
 linux-rel-css:
-  - ./mach build --release
+  - ./mach build --release --with-debug-assertions
   - ./mach test-css --release --processes 16 --log-raw test-css.log --log-errorsummary css-errorsummary.log
-  - ./mach build-cef --release
+  - ./mach build-cef --release --with-debug-assertions
   - ./mach build-geckolib --release
   - ./mach test-stylo --release
   - bash ./etc/ci/lockfile_changed.sh