pointer TypeInfo more conveniently. Have this class return true for
isSingleRetainablePointer(). Further specialize the implementations
of the value witnesses so that we no longer ever require type-specific
witnesses for reference types.
Swift SVN r1900
first, we weren't registering the cleanup for the temporary
if it needed materialization, and second, we were potentially
double-consuming cleanups associated with the l-value, e.g.
subscript indices.
Swift SVN r1631
heap allocations it makes, and switch swift_alloc over to pass
that pointer in as well as the alignment. Also, compute
whether a type is POD during its generation and cache that in
the object, and introduce a method on TypeInfo to destroy an
object in memory.
Swift SVN r1356
