Pass the aapcs and apcs features down to llvm.

No functionality change, but unblocks asserting that llvm's and clang's
datalayout strings are the same.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198306 91177308-0d34-0410-b5e6-96231b3b80d8
Remove the now unused 's' specifications.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198308 91177308-0d34-0410-b5e6-96231b3b80d8