* 2.8:
  [Form] Hardened test suite for empty data
  Bump phpunit XSD version to 5.2
  Add required key attribute

Some attributes being used in the phpunit configuration files, namely
failOnRisky and failOnWarning were introduced in phpunit 5.2.0. The
Composer configuration shows that tests should run with old versions of
phpunit, but phpunit only validates the configuration against the XSD
since phpunit 7.2.0.
These changes can be tested as follows:

wget http://schema.phpunit.de/5.2/phpunit.xsd
xargs xmllint --schema phpunit.xsd  1>/dev/null
find src -name phpunit.xml.dist| xargs xmllint --schema phpunit.xsd  1>/dev/null

See https://github.com/sebastianbergmann/phpunit/commit/7e06a82806be004cbfd30a02d92162e9ed4abc7c
See https://github.com/symfony/symfony/blob/46e3745a03e199e64cc0fcf3284a96b5a25dcee9/composer.json#L98

* 2.8:
  Fixed typo
  Fix ini_get() for boolean values

* 2.8:
  [php_cs] disable fopen_flags
  [CS] Remove unused variables passed to closures
  [CS] Remove empty comment
  [CS] Enforces null type hint on last position in phpDocs
  [CS] Use combined assignment operators when possible
  Fix a typo in error messages
  [Console] Add missing null to input values allowed types
  [PHPUnitBridge] Fix microtime() format
  bumped Symfony version to 2.8.47
  update CONTRIBUTORS for 2.8.46
  updated VERSION for 2.8.46
  updated CHANGELOG for 2.8.46

* 2.8:
  Enable native_constant_invocation CS fixer

This PR was merged into the 3.4 branch.

Discussion
----------

Use an empty string as default for assertEquals

Make sure it isn’t interpreted as a type NULL, making the test fail with PHPUnit 7.2.

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| License       | MIT

This shouldn’t break the existing tests, but will also make them work with recent PHPUnit.

Commits
-------

31353147a3 Use an empty string as default for assertEquals

* 2.8:
  Fix Clidumper tests
  Enable the fixer enforcing fully-qualified calls for compiler-optimized functions
  Apply fixers
  Disable the native_constant_invocation fixer until it can be scoped
  Update the list of excluded files for the CS fixer

Make sure it isn’t interpreted as a type NULL, making the test fail with
PHPUnit 7.2.

* 3.3:
  fixed years in copyright

* 2.8:
  fixed years in copyright

* 2.7:
  fixed years in copyright

* 3.3:
  Clean up
  Update return type in docblock.
  PHP CS Fixer: no need to exclude xml and yml files
  PHP CS Fixer: no need to exclude json file
  Update LICENSE year... forever

* 2.8:
  Clean up
  Update return type in docblock.
  PHP CS Fixer: no need to exclude xml and yml files
  Update LICENSE year... forever

* 2.7:
  Clean up
  Update return type in docblock.
  PHP CS Fixer: no need to exclude xml and yml files
  Update LICENSE year... forever

* 3.3:
  fixed some deprecation messages
  fixed some deprecation messages
  fixed some deprecation messages
  fixed some deprecation messages
  [2.7][DX] Use constant message contextualisation for deprecations

* 2.7:
  fixed some deprecation messages

* 3.3:
  [Serializer] Fix extra attributes when no group specified
  [Intl] Make intl-data tests pass and save language aliases again
  [Console] Fix CommandTester::setInputs() docblock
  [Serializer] readd default argument value
  [VarDumper] fix trailling comma when dumping an exception
  Remove useless docblocks
  [FrameworkBundle] Fix docblocks
  [PropertyInfo] Remove useless docblocks

* 2.8:
  [Intl] Make intl-data tests pass and save language aliases again
  Remove useless docblocks
  [PropertyInfo] Remove useless docblocks

* 2.7:
  [Intl] Make intl-data tests pass and save language aliases again
  Remove useless docblocks

* 3.3:
  [DI] minor docblock fixes

* 2.8:
  [DI] minor docblock fixes

* 2.7:
  [DI] minor docblock fixes