Implement printing of rvalue reference types and values

Implement printing of rvalue reference types and values

This patch provides the ability to print out names of rvalue reference types
and values of those types. This is done in full similarity to regular
references, and as with them, we don't print out "const" suffix because all
rvalue references are const.

gdb/ChangeLog

	PR gdb/14441
	* c-typeprint.c (c_print_type, c_type_print_varspec_prefix)
	(c_type_print_modifier, c_type_print_varspec_suffix)
	(c_type_print_base): Support printing rvalue reference types.
	* c-valprint.c (c_val_print, c_value_print): Support printing
	rvalue reference values.