[SystemZ] Implement A, O and R inline assembly format flags (#80685)

Implement the following assembly format flags, which are already
supported by GCC:

	'A': On z14 or higher: If operand is a mem print the alignment
         hint usable with vl/vst prefixed by a comma.
	'O': print only the displacement of a memory reference or address.
	'R': print only the base register of a memory reference or address.

Implement 'A' conservatively, since the memory operand alignment
information is not available for INLINEASM at the moment.