* Fix alpha channel dimensions in WebP lossless decoding
Use the expected width and height values instead of tempRaster.getWidth()/getHeight() when creating the alpha channel's writable child raster. This ensures the alpha channel is correctly sized when the temp raster dimensions differ from the expected dimensions.
* Fixes Lossless Huffman table based on libwebp
* Remove redundant flush call in image reader test
Removed unnecessary image.flush() call in WebPImageReaderTest.
* adding code to generate good hash for reproducability
1b889b1b4b