[HttpKernel] Remove unused method Kernel::isClassInActiveBundle

Follow-up of #11869
[PropertyAccess] Added test to verify #5775 is fixed
[Hackday] [2.7] Add a deprecation note about TypeTestCase
[HttpKernel] Added deprecated error to init()
[HttpKernel] fix deprecation notice for Kernel::init()
Add a deprecation note about CsrfProviderInterface
Add a deprecation note about VirtualFormAwareIterator
Fix deprecation notice on VirtualFormAwareIterator
[Form] Log deprecation of constants, fixes #12607 #12667
Test components using their lowest possible deps
minor #12542 Test components using their lowest possible deps (nicolas-grekas)

This PR was squashed before being merged into the 2.3 branch (closes #12542).

Discussion
----------

Test components using their lowest possible deps

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

Once https://github.com/composer/composer/pull/3450 is merged, we'll see if our deps are correct, and ensure that is kept over time by testing each component with its lowest possible deps.

Commits
-------

25fef27 Test components using their lowest possible deps
Fix return phpdoc
Fix placeholder date format
Merge remote-tracking branch 'symfony/2.3' into lowest-25

* symfony/2.3:
  Test components using their lowest possible deps

Conflicts:
	src/Symfony/Bridge/Doctrine/composer.json
	src/Symfony/Bridge/Twig/composer.json
	src/Symfony/Bundle/FrameworkBundle/composer.json
	src/Symfony/Bundle/SecurityBundle/composer.json
	src/Symfony/Bundle/TwigBundle/composer.json
	src/Symfony/Component/DependencyInjection/composer.json
	src/Symfony/Component/EventDispatcher/composer.json
	src/Symfony/Component/Form/composer.json
	src/Symfony/Component/HttpKernel/composer.json
	src/Symfony/Component/Routing/composer.json
	src/Symfony/Component/Security/composer.json
	src/Symfony/Component/Validator/composer.json
[2.3] Docblocks should not be followed by a blank line
minor #12993 [2.3] Docblocks should not be followed by a blank line (GrahamCampbell)

This PR was squashed before being merged into the 2.3 branch (closes #12993).

Discussion
----------

[2.3] Docblocks should not be followed by a blank line

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

There should be no blank line(s) between phpdocs that document properties, interfaces, classes, functions, or traits. This pull request was a test run of a new php-cs-fixer: https://github.com/FriendsOfPHP/PHP-CS-Fixer/pull/864.

Commits
-------

4e7ba1b [2.3] Docblocks should not be followed by a blank line
minor #12985 [HttpFoundation] Fix return phpdoc (Koc)

This PR was merged into the 2.3 branch.

Discussion
----------

[HttpFoundation] Fix return phpdoc

| Q             | A
| ------------- | ---
| Bug fix?      | tiny (for IDE autocompletion)
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

What about using `self` or `static` keyword for this?

Commits
-------

9af2d81 Fix return phpdoc
bug #12996 [WebProfilerBundle] Fix placeholder date format (mvar)

This PR was merged into the 2.6 branch.

Discussion
----------

[WebProfilerBundle] Fix placeholder date format

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #12995
| License       | MIT
| Doc PR        | -

Commits
-------

9a44aa8 Fix placeholder date format
[FrameworkBundle] fix cache:clear command
Test lowest versions of dependencies