* Split unit test over multiple jobs in GitHub Actions, lowering the total run time
* rename FileManipulationTest to FileManipulationTestCase so it does not run as a standalone Test
* add support for Psalter to remove UnusedVariable
* fix issues found by Psalm
* fix stylistic issues found by phpcs
* added more stylistic changes and suppressed UndefinedClass error for Psalm
* suppress TypeDoesNotContainType error for CheckTrivialExprVisitor
* fix whitespace issue raised by phpcs
* fix bug where partial removal of assignment by ref does not process '&' symbol
* Remove workspace files
* remove 'Array_' and 'ArrayItem' classes from blacklist and add 'New_' class to the blacklist