API: Rename disablepp and introduce disabletidy
* Rename disablepp to disablelimitreport, since it does not disable the
preprocessor (which is what PP stands for in "NewPP").
* Introduce new option "disabletidy" for T89331
* Suppress the use of the parser cache when options are specified that
affect the output but are not in ParserOptions::optionsHash(). This
was already broken, but the damage was fairly limited since the
options rarely caused user-visible changes. It would break very badly
if I use the disabletidy option for what I am intending.
Change-Id: I4b0e55fe34e237a68450f583bf59bab7dd703a29