Enable support for returning i1, i8, and i16. Nothing special todo as it's the

Enable support for returning i1, i8, and i16.  Nothing special todo as it's the
callee's responsibility to sign or zero-extend the return value.  The additional
test case just checks to make sure the calls are selected (i.e., -fast-isel-abort
doesn't assert).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144047 91177308-0d34-0410-b5e6-96231b3b80d8