lto.c (iterative_hash_canonical_type, [...]): only hash main variants of types

lto.c (iterative_hash_canonical_type, [...]): only hash main variants of types

	* lto.c (iterative_hash_canonical_type,
	gimple_register_canonical_type): only hash main variants of types
	* tree.c (verify_type_variant): Verify that type and variant is
	compatible.
	(gimple_canonical_types_compatible_p): Look for main variants.

From-SVN: r224107