cp-demangle.c (d_print_comp): Don't push more than one of the same CV-qualifier on the top of the stack.

	* cp-demangle.c (d_print_comp) [RESTRICT, VOLATILE, CONST]: Don't
	push more than one of the same CV-qualifier on the top of the
	stack.
	(d_print_comp) [ARRAY_TYPE]: If the array itself is CV-qualified,
	move the CV-qualifiers to apply to the element type instead.
	(d_print_array_type): When checking the modifiers, keep looking
	past ones which have been printed already.
	* testsuite/demangle-expected: Add three test cases.

From-SVN: r78354