<rdar://problem/13863031>

Giving a timeout for the call to NSPrintForDebugger() that happens when you “po” objects

This is a temporary workaround until a more detailed solution to the general problem of canceling actions is found

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@182782 91177308-0d34-0410-b5e6-96231b3b80d8