Fixed saving TIFF multiframe images with LONG8 tag types

[radarhere]

Resolves #7077

The issue points out that

Pillow/src/PIL/TiffImagePlugin.py

Lines 1881 to 1895 in b0c7653

	fieldSizes = [
	0, # None
	1, # byte
	1, # ascii
	2, # short
	4, # long
	8, # rational
	1, # sbyte
	1, # undefined
	2, # sshort
	4, # slong
	8, # srational
	4, # float
	8, # double
	]

does not include 'long8', which we first started supporting in #6097.

This PR adds 'long8', https://www.awaresystems.be/imaging/tiff/bigtiff.html

TIFF_LONG8 = 16, being unsigned 8byte integer

but because fieldSizes is a list not a dictionary, the items between 12 ("12 = DOUBLE") and 16 also need to be added.

https://www.awaresystems.be/imaging/tiff/specification/TIFFPM6.pdf

TIFF data type 13, “IFD,” is otherwise identical to LONG

So 'ifd' has size 4, like long.

For 14 and 15, information is scarce. The best information I could find was
https://android.googlesource.com/platform/external/dng_sdk/+/refs/heads/master/source/dng_tag_types.h

ttByte = 1,
ttAscii,
ttShort,
ttLong,
ttRational,
ttSByte,
ttUndefined,
ttSShort,
ttSLong,
ttSRational,
ttFloat,
ttDouble,
ttIFD,
ttUnicode,
ttComplex

https://android.googlesource.com/platform/external/dng_sdk/+/refs/heads/master/source/dng_image_writer.cpp#325

// Two byte entries.
...
  case ttUnicode:
...
// Four byte entries.
...
  case ttComplex: