[SecurityBundle] Move format-dependent tests from SecurityExtensionTest
merged branch unkind/security-bundle-tests-restructuring (PR #8840)

This PR was squashed before being merged into the 2.2 branch (closes #8840).

Discussion
----------

[SecurityBundle] Move format-dependent tests from SecurityExtensionTest

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

This PR solves issue with tests in the SecurityBundle: current structure of tests force to repeat the same test case for every format (PHP, XML, YAML) even if it doesn't depend on them (see #8782).

Commits
-------

d463e25 [SecurityBundle] Move format-dependent tests from SecurityExtensionTest
[FrameworkBundle] added support for double-quoted strings in the extractor (closes #8797)
merged branch fabpot/extrator-fix (PR #8869)

This PR was merged into the 2.2 branch.

Discussion
----------

[FrameworkBundle] added support for double-quoted strings in the extractor (closes #8797)

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #8797
| License       | MIT
| Doc PR        | n/a

Commits
-------

4922a80 [FrameworkBundle] added support for double-quoted strings in the extractor (closes #8797)
Merge branch '2.2' into 2.3

* 2.2:
  [FrameworkBundle] added support for double-quoted strings in the extractor (closes #8797)
  [SecurityBundle] Move format-dependent tests from SecurityExtensionTest

Conflicts:
	src/Symfony/Bundle/SecurityBundle/Tests/DependencyInjection/SecurityExtensionTest.php