[lldb] try to fix build on linux after fc6b7252

Tries to fix:

    ../../lldb/source/Breakpoint/WatchpointResource.cpp:59:12:
    error: no member named 'find' in namespace 'std'; did you mean 'fill'?
          std::find(m_constituents.begin(), m_constituents.end(), wp_sp);
          ~~~~~^~~~
               fill

(cherry picked from commit a6c62bf1)