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.
Commit back the correct bits of r222760 (was r222538).

I also added a test.

Original message:

Allow FDE references outside the +/-2GB range supported by PC relative
offsets for code models other than small/medium. For JIT application,
memory layout is less controlled and can result in truncations
otherwise.

Patch from Akos Kiss.

Differential Revision: http://reviews.llvm.org/D6079