Set the expected result of the test `tex-input-validation.html` to CRASH, since
that is caused by unrelated problems. The test was previously not executing
completely, because it stopped when it didn't find the implementation of
getTexParameter.
Use specific assertions
Similar to #19865
r? jdm
Note: Should I squash all the commits into one commit?
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes do not require tests because it should not break anything
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