* 2.6:
[Debug] Fix log level of stacked errors
[VarDumper] Fix uninitialized id in HtmlDumper
Fixed fluent interface
[Debug] fix debug class loader case test on windows
[Debug+VarDumper] Fix handling of PHP7 exception/error model
[2.6][Security][Translation] #14920 update translations
[VarDumper] Cherry-pick code style fixes from 2.7
Bug #14836 [HttpFoundation] Moves default JSON encoding assignment from constructor to property
Conflicts:
src/Symfony/Component/Debug/Tests/DebugClassLoaderTest.php
src/Symfony/Component/VarDumper/Caster/DOMCaster.php
src/Symfony/Component/VarDumper/Caster/ExceptionCaster.php
src/Symfony/Component/VarDumper/Caster/PdoCaster.php
src/Symfony/Component/VarDumper/Caster/SplCaster.php