Memory map rotated TIFF images at stored size

[lazerg]

An uncompressed single-strip TIFF with Orientation 5-8 that isn't square comes out scrambled when opened by filename. Since #8390, size is the displayed (transposed) size and _tile_size holds the stored size, but the mmap branch of ImageFile.load() still mapped the buffer at self.size, so the stored rows were read at the wrong width before load_end() transposed them.

This maps the buffer, and runs the length check from #10147, at _tile_size when the image has one. Added a test for orientations 5-8.

Fixes #10220

[radarhere]

Thanks. I've created lazerg#7 with a suggestion.

[lazerg]

Thanks, merged. I switched the test back to hopper("L") in 85dc302, since RGB isn't memory mapped and the test passed even without the fix. Also, if load() raises, _size stays at the stored size, so a try/finally might be worth adding.

[radarhere]

Ah, yes, thanks. I've pushed a commit to add a try block.