Remove symbolics from irange.

Remove symbolics from irange.

gcc/ChangeLog:

	* value-range.cc (irange::copy_legacy_to_multi_range): Remove
	symbolics support.
	(irange::set): Same.
	(irange::legacy_lower_bound): Same.
	(irange::legacy_upper_bound): Same.
	(irange::contains_p): Same.
	(range_tests_legacy): Same.
	(irange::normalize_addresses): Remove.
	(irange::normalize_symbolics): Remove.
	(irange::symbolic_p): Remove.
	* value-range.h (class irange): Remove symbolic_p,
	normalize_symbolics, and normalize_addresses.
	* vr-values.cc (simplify_using_ranges::two_valued_val_range_p):
	Remove symbolics support.