Add range_on_entry/exit to value_query API.

Add range_on_entry/exit to value_query API.

Add range_on_entry and range_on_exit to the value_query API.  These will
also work with generic trees like range_of_expr does.

	* gimple-range.cc (gimple_ranger::range_on_entry): Adjust for new
	API and support non-SSA expressions.
	(gimple_ranger::range_on_exit): Ditto.
	* gimple-range.h (range_on_entry, range_on_exit): Adjust API.
	* value-query.cc (range_query::range_on_entry): New.
	(range_query::range_on_exit): New.
	(range_query::value_on_entry): New.
	(range_query::value_on_exit): New.
	(range_query::invoke_range_of_expr): New.
	(range_query::get_tree_range): Allow stmt, on_entry or on_exit
	range queries.
	SSA_NAMES should invoke range_of_expr if possible.
	* value-query.h (class range_query): Adjust prototypes.