swift234

Remove FuncDecl::throws(). NFC

FuncDecl::throws() is misleading because it only tells us whether the
'throws' keyword was present on the declaration. Since source
locations are lost during deserialization, it would give the wrong
result. Nobody was making this mistake now, but it's better not to
leave this trap in the ASTs.

Use AbstractFuncitonDecl::isBodyThrowing() to determine whether a
particular function (or initializer, eventually) can throw.

Swift SVN r27257