swift

e56a4e24 - Add a `MemoryLayout<T>.offset(of:)` method for getting the offset of inline storage.

Add a `MemoryLayout<T>.offset(of:)` method for getting the offset of inline storage. If a key path refers to inline storage of the root type, this produces the offset in bytes between a pointer to the root and a pointer to the projected storage. Otherwise, returns nil. (cherry picked from commit a6a792c7407502c87eb7e20f9aa6c01ae023bedb)