Add tp_richcompare handler for Imaging_Type/ImagingCore

[Yay295]

Imaging_Type/ImagingCore is exposed by Image.getdata(), so this allows you to properly compare the result of that method without it being an identity comparison. This should also speed up comparison between Image objects, because now the comparison is done in C instead of passing the data back to Python for it to be compared.

[radarhere]

Valgrind is currently failing - https://github.com/python-pillow/Pillow/actions/runs/5460694184/jobs/9937936242?pr=7260

Also, I went to test the speed of image equality with this, radarhere@98e02aa... and found https://github.com/radarhere/Pillow/actions/runs/5461893489/jobs/9940492884#step:8:4787

Fatal Python error: bool_dealloc: deallocating True or False: bug likely caused by a refcount error in a C extension

[Yay295]

oops, Py_NewRef wasn't added until Python 3.10.

[radarhere]

Imaging_Type/ImagingCore is exposed by Image.getdata(), so this allows you to properly compare the result of that method without it being an identity comparison.

#9292 deprecated this.

[radarhere]

@akx did you have any thoughts on this PR? It seems related to other work currently being discussed.

[akx]

@radarhere Yep, tangentially related to #9883, but also #9938! I'm all for faster image comparison that doesn't involve dumping both images into a secondary buffer...

I can do the work to forward-port this to the new mode ID stuff and so on. 👍