Reenable the logic to take an integer value and attempt to "po" it as an ObjC object

While there is quite a bit of potential for mishaps due to tagged pointers, and after quite some internal discussion, this seems a saner behavior given how "po" stands for "print OBJECT". The argument being that we should make at least some sensible attempt to print the thing the user passed as-if it was an object

Fixes rdar://19423124

llvm-svn: 226062