[DependencyInjection] Add a method map to avoid computing method names from service names
merged branch Seldaek/methodmap (PR #7933)

This PR was merged into the master branch.

Discussion
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[DependencyInjection] Add a method map to avoid computing method names from service names

/cc @schmittjoh @stof

The diff is a bit messy because of indenting, but all this adds really is an `if(isset($this->methodMap[$id])) { $method = $this->methodMap[$id]; }` that bypasses the method_exists + strtr calls. It's not a huge improvements but saves some cycles on something that's typically called a few hundred times per request.

Commits
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f1c2ab7 [DependencyInjection] Add a method map to avoid computing method names from service names