Clang sometimes emits "objc_object*" rather than "id"
for id types with protocols on them.  We detect this
and report "id" instead.

Also added a testcase.

<rdar://problem/12595644>


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@171431 91177308-0d34-0410-b5e6-96231b3b80d8