tree.c (initialize_tree_contains_struct): Make TS_OPTIMIZATION and TS_TARGET_OPTION directly derive from TS_BASE.

2017-01-12  Richard Biener  <rguenther@suse.de>

	* tree.c (initialize_tree_contains_struct): Make TS_OPTIMIZATION
	and TS_TARGET_OPTION directly derive from TS_BASE.
	* tree-core.h (tree_optimization_option): Derive from tree_base.
	(tree_target_option): Likewise.

From-SVN: r244349