Revert "Reapply 222538 and update tests to explicitly request small code model and PIC:"

This reverts commit r222760.

It changed our behaviour on PIC so we don't match gas anymore. It also
included lots of unnecessary changes to tests.

If those changes are desirable, there should be an independent discussion
as they are out of scope for that patch.

I will recommit the other bits.

llvm-svn: 222896