SystemRuntime/MacOSX no longer need ObjCRuntime header.

Summary:
The AppleGetQueuesHandler code no longer needs to include a header
from the AppleObjCRuntime, so we can remove workarounds that were
present in the build systems.

Reviewers: clayborg, jasonmolenda

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D12589

llvm-svn: 246821