Add new iclass sve_size_bh to handle instructions that have two variants
encoded with the SVE_sz field.
This iclass behaves the same as the sve_size_sd iclass, but it has a
nicer name for those instructions that choose between variants using the
"B" and "H" size qualifiers.
include/ChangeLog:
2019-05-09 Matthew Malcomson <matthew.malcomson@arm.com>