[Driver][Darwin] Pass -munwind-table when !UseSjLjExceptions.

[Driver][Darwin] Pass -munwind-table when !UseSjLjExceptions.

This commit fixes a bug where clang/llvm doesn't emit an unwind table
for a function when it is marked noexcept. Without this patch, the
following code terminates with an uncaught exception on ARM64:

int foo1() noexcept {
  try {
    throw 0;
  } catch (int i) {
    return 0;
  }
  return 1;
}

int main() {
  return foo1();
}

rdar://problem/32411865

Differential Revision: https://reviews.llvm.org/D35693

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@310006 91177308-0d34-0410-b5e6-96231b3b80d8