Make `\Request::get` more performant.
Fix typo
reformat code as suggested by @fabpot
minor #12537 [HttpFoundation] Make Request::get() more performant (KorvinSzanto, xabbuh)

This PR was submitted for the 2.7 branch but it was merged into the 2.3 branch instead (closes #12537).

Discussion
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[HttpFoundation] Make Request::get() more performant

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

This finishes the work started by @KorvinSzanto in #12369.

Commits
-------

3039935 reformat code as suggested by @fabpot
ad64223 Fix typo
4162713 Make `\Request::get` more performant.