Add support for reading CPUID in drutil_opnd_mem_size_in_bytes to determine the size of the memory reference of xsave. The final size of written bytes depends on runtime data in the instruction's operand and can therefore not be determined statically. This and other limitations are mentioned in a comment in drutil.
Add basic test for drutil_opnd_mem_size_in_bytes and xsave.
Add a function instr_is_xsave() to return whether the instruction is part of the xsave family of instructions.
Issue: #2946 (closed)