<!-- Please describe your changes on the following line: -->
- Fix crop_area_bytes_length calculation (the height was multiplied by itself)
- Add tests for this error and for the case that the width is multiplied by itself
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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#15386
<!-- Either: -->
- [X] There are tests for these changes
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Source-Repo: https://github.com/servo/servo
Source-Revision: 594a679002a5d74da761c17574ad5383a130b55a
b8f070088b