[IntrinsicEmitter] Make AttributesMap bits adaptive (#157965)
Make IntrinsicsToAttributesMap's func. and arg. fields be able to have
adaptive sizes based on input other than hardcoded 8bits/8bits.
This will ease the pressure for adding new intrinsics in private
downstreams.
func. attr bitsize will become 7(127/128) vs 8(255/256)