Merge branch 'hotfix/#5956-zend-json-server-options-enforced-as-array'

Close #5956
explicitly add properties and corresponding docblocks
[#5651] test module loading, infinite looping, and circular deps
Adding `@group` annotation for tests of #5948
Merge branch 'tests/#5948-circular-dependency-tests-for-module-manager-init'

Close #5948
Fixes #5929 - Remove a page recursively
NumberOfParameterFilter correctly handles argument count greater than zero.
Return boolean instead of if statement.
Fixes #6082
Cleaned up annotations for tests of #6083
Merge branch 'hotfix/#6083-hydrator-number-of-parameters-filter-honored'

Close #6083
Adding failing test case for #6089 - serialization causes notices
Hotfix for #6089 - `protectedProperties` of ArrayObject are maintained on serialization
add fix and unit test for the case where Filesystem::clearByPrefix() can try to remove a directory (eg if the prefix happens to collide with a partial md5 key), as pointed out by @marc-mabe in issue 6076
php_cs whitespace cleanup
add unit test for clearExpired exception. By setting the cache dir to read-only, unlink() will fail, causing the exception event to be triggered.
Ensure that an empty ArrayObject is passed to triggerException - null does not work
php_cs fixes
set exceptionHandler plugin to not throw exceptions, to prove that the exception event is handled as expected.
Add use statements for plugin and options.
Fix unused imports
Remove unused variables