search.c: Tear out all mi_matrix and memoize code.

search.c: Tear out all mi_matrix and memoize code.

	* search.c: Tear out all mi_matrix and memoize code.
	(lookup_field, lookup_fnfields): Use scratch_tree_cons.
	* lang-options.h: Remove documentation for -fhandle-exceptions,
	-fmemoize-lookups and -fsave-memoized.
	* cp-tree.h: Lose mi_matrix and memoize support.
	* decl2.c: Ignore -fmemoize-lookups and -fsave-memoized.
	* class.c: Lose struct class_level.
	(pushclass, popclass): Lose memoize support.
	* init.c (build_offset_ref): Likewise.

From-SVN: r22025