Upgrade the libtiffpic test harness from decode-only smoke tests to
full output verification using CRC32 reference hashes. 50 of 61 images
now have hash-verified decoded output; the remaining 11 use unsupported
formats (YCbCr subsampling, Fax3, etc.) and remain as decode-only tests.
Uses read_image_to_buffer (the non-deprecated API) with ByteOrder::convert
for cross-platform LE normalization.
Remove the 13 individual depth tests from decode_images.rs — they tested
the same libtiffpic flower images that are now hash-verified here.
Two tests are disabled, both related to tiles, since they do not follow
the fully released spec themselves but incidentally decode with libtiff
anyways. The two images (`cramps-tile.tif`, `quad-tile.tif`) are tiled
layout which libtiff detects by the presence of TileWidth/TileHeight
tags. We would detect that by chunks encoded via TileOffsets and
TileByteLengths tags. However the images encoded their chunk data into
the StripOffsets tag; additionally they contain a RowsPerStrip value
anyways.
Tests disabled as this is to be resolved in a separate issue (#338) with
a decision on treatment of this situation (strictness setting or copying
libtiff, also error late for mismatched lengths).
Lilith River