target.def: Add code_for_* hooks.

target.def: Add code_for_* hooks.

gcc/
	* target.def: Add code_for_* hooks.
	* gentarget-def.c (def_target_insn): Add TARGET_CODE_FOR_* macros.
	* defaults.h (HAVE_tablejump, gen_tablejump): Delete.
	* target-insns.def (casesi, tablejump): New targetm instruction
	patterns.
	* expr.c (try_casesi): Use them instead of HAVE_*/gen_* interface.
	(do_tablejump): Likewise.
	* stmt.c (expand_switch_as_decision_tree_p): Likewise.
	(expand_sjlj_dispatch_table): Likewise.
	* targhooks.c (default_case_values_threshold): Likewise.

From-SVN: r225421