* `pass` is consistently inserted on the new line now
* excess spaces left after element was deleted are removed
Use PyUtil#deleteElementSafely in pull, push and extract superclass
refactoring implementations.
It turned out that all problems with whitespaces left after we moved
function are rooted in awkward implementation of PyFunctionImpl#delete()
that delegated to plain AST manipulation and thus ignored
usual additional reformatting step. I removed it and it's allowed to
clean a lot of test files and remove the code that was added previously
exactly for this purpose in PyMoveSymbolProcessor.
