* 3.4:
[YAML] Issue #26065: leading spaces in YAML multi-line string literals
[Bridge\PhpUnit] Exit as late as possible
[Bridge\PhpUnit] Cleanup BC layer
[PhpBridge] add PHPUnit 7 support to SymfonyTestsListener
[Lock] Log already-locked errors as "notice" instead of "warning"
add context to serialize and deserialize
Update Repository Symlink Helper
Document explicitly that dotfiles and vcs files are ignored by default
[HttpKernel] don't try to wire Request argument with controller.service_arguments
Make kernel build time optionally deterministic
Use 0 for unlimited expiry
[Routing] fix typo
Bump default PHPUnit version from 6.3 to 6.5
do not mock the container builder in tests
[Cache][WebProfiler] fix collecting cache stats with sub-requests + allow clearing calls
