Provide interface for non-standard operators.

Provide interface for non-standard operators.

THis removes the hack introduced for WIDEN_MULT which exported a pointer
to the operator and the gimple-range-op.cc set the operator to this
pointer whenn it was appropriate.

Instead, we simple change the range-op table to be unsigned indexed,
and add new opcodes to the end of the table, allowing them to be indexed
directly via range_op_handler::range_op.

	* gimple-range-op.cc (gimple_range_op_handler::maybe_non_standard):
	Use range_op_handler directly.
	* range-op.cc (range_op_handler::range_op_handler): Unsigned
	param instead of tree-code.
	(ptr_op_widen_plus_signed): Delete.
	(ptr_op_widen_plus_unsigned): Delete.
	(ptr_op_widen_mult_signed): Delete.
	(ptr_op_widen_mult_unsigned): Delete.
	(range_op_table::initialize_integral_ops): Add new opcodes.
	* range-op.h (range_op_handler): Use unsigned.
	(OP_WIDEN_MULT_SIGNED): New.
	(OP_WIDEN_MULT_UNSIGNED): New.
	(OP_WIDEN_PLUS_SIGNED): New.
	(OP_WIDEN_PLUS_UNSIGNED): New.
	(RANGE_OP_TABLE_SIZE): New.
	(range_op_table::operator []): Use unsigned.
	(range_op_table::set): Use unsigned.
	(m_range_tree): Make unsigned.
	(ptr_op_widen_mult_signed): Remove.
	(ptr_op_widen_mult_unsigned): Remove.
	(ptr_op_widen_plus_signed): Remove.
	(ptr_op_widen_plus_unsigned): Remove.