vulkan: support non-contig unary/glu ops (#24215)

• vulkan: support non-contig unary/glu ops

Change unary/glu ops to pass in all strides and use fastdiv for the index calculation. Put all unary ops in one file, similar to glu, to share the code. codex went ahead and added expm1 without me asking, but I had to make it do a real precision analysis rather than just making stuff up.

unary.comp initially couldn't use generic_unary_head because there wasn't space for xielu's additional constants. Fixing this required packing the fastdiv 'L' values.

• attempt to workaround compiler bug

• resolve conflict from #23991

• use expm1