Disable EHFrameSupport in JITLink/RuntimeDyld on AIX

Summary:
EH Frames aren't supported on AIX with the system compiler, but the definition of HAVE_EHTABLE_SUPPORT misses this which causes linking problems on AIX. This patch updates the definition of HAVE_EHTABLE_SUPPORT in both JITLink and RuntimeDyld.

Author: daltenty

Reviewers: sfertile, xingxue, hubert.reinterpretcase

Reviewed By: xingxue

Subscribers: hiraditya, jsji, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62203

llvm-svn: 361410