[TASK] Enable "pageNotFoundOnCHashError" by default

The setting pageNotFoundOnCHashError should be true by default for
perfomance reasons: If it is true, a 404 error is thrown when an invalid
cHash is found. This is way faster than re-rendering an otherwise cached
page (and then not caching it because of the invalid cHash).

Change-Id: I384e5ba5c2954a9c25d2124e728b2bbb06802340
Resolves: #45287
Releases: 6.1
Reviewed-on: https://review.typo3.org/18121
Reviewed-by: Andreas Wolf
Tested-by: Andreas Wolf