[ptr-traits] Sink several in-body method definitions to be out-of-line

inline definitions after the mutually recursive pair of types have been
defined. The two types mutually recurse specifically through
abstractions that require pointer traits which makes this kind of mutual
recursion especially tricky to get right in terms of ordering.

This is part of a series of patches to allow LLVM to check for complete
pointee types when computing its pointer traits. This is absolutely
necessary to get correct (or reproducible) results for things like how
many low bits are guaranteed to be zero.

llvm-svn: 256551