Remove parameter checking

[oakleybrunt]

I have spoken with Ben Went today and had a look over the helper functions he has been using (separately to PSyTran), and I noticed that he had a lot of parameter checking before any functionality. He said that he was following the style laid out in PSyTran.

After reviewing how PSyTran does things, it does seem like there is a lot of parameter checking happening (for safety, I understand). However, this is not a habit I want people to get into - PSyclone will give an error if the types are wrong. For example, in apply_loop_directive a check is performed on the options parameter to see if it is a dictionary. If a non-dict object is passed here, PSyclone provides this error message:

psyclone.psyir.transformations.transformation_error.TransformationError: Transformation Error:
Transformation validate method 'options' argument must be a dictionary but found 'list'.

I propose that all type checking is removed (unless absolutely necessary) since PSyclone handles this.