When continuing to use a page object after the PDF has been saved with garbage options may change the MuPDF cache such that e.g. rendering the page after the save will produce wrong appearance or even garbled appearance.
The user needs to reload the page (page = doc.reload(page)) before using it further, especially for rendering.
The reload method now always empties the cache.

The underlying fz_page was being kept alive so reload_page()'s call of
fz_load_page() was returning it from the document's internal list of pages
instead of regenerating it.