[DependencyInjection] made some perf improvements
minor #10241 [DependencyInjection] made some perf improvements (fabpot)

This PR was merged into the 2.6-dev branch.

Discussion
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[DependencyInjection] made some perf improvements

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

This PR optimizes the creation of dumped containers drastically (thanks @jpauli for the hint).

The Container class generated by the PHP dumper does not include the `getDefaultParameters()` method anymore. It does not seem like a big deal to me as I fail to see a use case where someone would override this method.

Commits
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e1a3ef8 [DependencyInjection] made some perf improvements