Added support for pulling Objective-C class symbols
out of the runtime.  This allows calling static methods
on classes whose symbols have been stripped out of the
binary.

<rdar://problem/12042992>


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@180210 91177308-0d34-0410-b5e6-96231b3b80d8