Perf php dumper

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Well, IIRC, we thought that removing it in the *minor* version was an acceptable BC break, because it breaks BC only for a really weird edge case: people writing a class extending the dumped one and changing/using the method to get default parameters