i#3635: Add missing TYPE_VAR_REGX to diassemble noimplicit operands. (#3643)
i#3635: Add missing TYPE_VAR_REGX to diassemble noimplicit operands. (#3643)

Adds missing type exposed by mulx in api.ir.

Fixes #3635
AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio