Allow uncompressed TIFF images to be saved in chunks

[radarhere]

Helps #4669

The issue would like to save a large TIFF image, but to do so in chunks, read then loading the entire image into memory at once.

If libtiff isn't used when saving, then the data is saved simply using the "raw" encoder.

So then what if one just appended data to a created image? The header would still need to change so that the image knew about the new size.

from PIL import Image, TiffImagePlugin

im = Image.open("Tests/images/hopper.png")
with open("out.tiff", "wb") as fp:
  for i, chunk in enumerate([
    im.crop((0, 0, 128, 32)),
    im.crop((0, 32, 128, 64)),
    im.crop((0, 64, 128, 96)),
    im.crop((0, 96, 128, 128)),
  ]):
    if i == 0:
      chunk.save(fp, "TIFF", tiffinfo={
        TiffImagePlugin.IMAGEWIDTH: 128,
        TiffImagePlugin.IMAGELENGTH: 128
      })
    else:
      fp.write(chunk.tobytes())

The image is the right size, but black.

When calculating stride, ifd[ROWSPERSTRIP] and ifd[STRIPBYTECOUNTS], TiffImagePlugin currently uses the image size. This PR updates it to use ifd[IMAGEWIDTH] and ifd[IMAGELENGTH], and then the saved image appears correctly.

Apart from this scenario, ifd[IMAGEWIDTH] and ifd[IMAGELENGTH] are supposed to be the same as image width and height. Two of the tests had to be updated when saving TIFF images using existing info, but I could argue that they were already incorrect in main for saving images with an incorrect ifd[IMAGEWIDTH].

[hugovk]

Needs a conflict resolving.