<rdar://problem/13265297> 

StackFrame assumes m_sc is additive, but m_sc can lose its target. So now the SymbolContext::Clear() method takes a bool that indicates if the target should be cleared. Modified all existing code to properly set the bool argument.



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@175953 91177308-0d34-0410-b5e6-96231b3b80d8