[range-ops] Add tree code to range_operator.

[range-ops] Add tree code to range_operator.

This patch adds a tree code to range_operator in order to known which
tree code to pass into bit-CCP.

Up to now range-ops has been free of tree details, with the exception
of the div entries which use a tree code to differentiate between
them.  This is still the goal going forward, but this is a stop-gap
until we can merge the CCP and range-op bit handling in the next
release.

No change in performance.

gcc/ChangeLog:

	* range-op.cc: (range_op_table::set): Set m_code.
	(integral_table::integral_table): Handle shared entries.
	(pointer_table::pointer_table): Same.
	* range-op.h (class range_operator): Add m_code.