[Security][Acl] Issue #5787 : Added MutableAclProvider::deleteSecurityIdentity

Code style fix and documentation typo
adds support for PTY mode
adds convenience method mustRun
attempts to fix tests on Travis
adds cache for isPtySupported()
[FrameworkBundle] made sure that the debug event dispatcher is used everywhere
remove deprecated constraints calls (Min, Max, MaxLength, MinLength)
[Form] Fixed memory leak in FormValidator
[Console] make InputArgument::setDefault() chainable
fixed wrong started states
bug #9246 [Session] fixed wrong started state (tecbot)

This PR was submitted for the master branch but it was merged into the 2.2 branch instead (closes #9246).

Discussion
----------

[Session] fixed wrong started state

Currently the session stays in the started mode after the call of  ```save()``` which will close the session. We found the issue in our custom SAPI which keeps the symfony stack initialized over multiple requests.

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

Commits
-------

d641cd6 [Session] fixed wrong started states
Fix in ChainLoader.php

The LoaderInterface requires the time to be passed.
bug #9270 [Templating] Fix in ChainLoader.php (janschoenherr)

This PR was submitted for the master branch but it was merged into the 2.2 branch instead (closes #9270).

Discussion
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[Templating] Fix in ChainLoader.php

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

The LoaderInterface requires the _time_ parameter to be passed.

Commits
-------

2631eb3 [Templating] Fix in ChainLoader.php
[Yaml] Fixed the escaping of strings starting with a dash when dumping

Dashes need to be escaped in character sets in regexes as they are used to
specify a range otherwise.
Refs #9039
bug #9274 [Yaml] Fixed the escaping of strings starting with a dash when dumping (stof)

This PR was merged into the 2.2 branch.

Discussion
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[Yaml] Fixed the escaping of strings starting with a dash when dumping

Dashes need to be escaped in character sets in regexes as they are used to specify a range otherwise.
It fixes the dumper bug reported in #9039 (the parsing issue is not fix here)

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | partially #9039
| License       | MIT
| Doc PR        | n/a

Commits
-------

af369ae [Yaml] Fixed the escaping of strings starting with a dash when dumping
[Console] make parent constructor test more reliable

it also fixes the test since f2b60e9c687 and improves phpdoc
[Console] improve regex performance to validate name

using possesive quantifier
Remove unnecessary continue from Request
minor #9278 [HttpFoundation] Remove unnecessary continue from Request (tgabi333)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #9278).

Discussion
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[HttpFoundation] Remove unnecessary continue from Request

Commits
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067f561 [HttpFoundation] Remove unnecessary continue from Request
fix typo : StdClass should be stdClass with little "s"