Adjust operators equal and not_equal to check bitmasks against constants

Adjust operators equal and not_equal to check bitmasks against constants

Check to see if a comparison to a constant can be determined to always
be not-equal based on the bitmask.

	PR tree-optimization/111766
	gcc/
	* range-op.cc (operator_equal::fold_range): Check constants
	against the bitmask.
	(operator_not_equal::fold_range): Ditto.
	* value-range.h (irange_bitmask::member_p): New.

	gcc/testsuite/
	* gcc.dg/pr111766.c: New.