Objective-C error recovery. This patch makes a quick
recovery form duplicate method definition error thus
preventing doc parsing to loop trying to find comment
for the invalid redefinition in a previous declaration.
// rdar://13836387


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181710 91177308-0d34-0410-b5e6-96231b3b80d8