Fix readMetadataBoundsOfSuperclass to recursively apply adjustForSubclass while going through the superclass chain.
Strip indirect descriptor pointers so we can deal with signed pointers here.
Make CMemoryReader assert (in asserts builds) that the addresses being read don't have any signature bits set, which helps track down places where we need to add stripping.
rdar://134448718
The CMemoryReader interface relies on a `GetStringLength` callback, which
returns zero either if the address is invalid or if a valid zero-length
string exists at the given address. We don't want to break ABI with
RemoteMirror, but we can work around this by issuing a one-byte read
at the address and confirming that a null terminator exists there.
* Change the RemoteMirror API to have extensible data layout callback
* Use DLQ_Get prefix on DataLayoutQueryType enum values
* Simplify MemoryReaderImpl and synthesize minimalDataLayoutQueryFunction
This tool should test the usage from SwiftRemoteMirror dylib and
the C API, since that is the public interface from which we're
vending the remote reflection functionality.
Memory readers on the C-side of the API may actually have an object-
oriented design, so they may want to pass an instance to revive
when callbacks make it to the other side of the API boundary.
