[examples][ORC] Make sure eh-frame registration code is linked into an example.

Since aedeb8d5, which switched to EPC-based eh-frame registration, the
eh-frame registration functions need to be forcibly linked into the target
process.

We need a general solution to this problem, but for now just force it in this
example to fix the test failures in
https://green.lab.llvm.org/green/job/clang-stage1-RA/31497

rdar://101083784