[lldb] Make TestModuleLoadedNotifys work with dyld from the shared cache

Make TestModuleLoadedNotifys work with a dyld from the expanded shared
cache in the DeviceSupport directory. In that case the module path is:

  ~/Library/Developer/Xcode/iOS DeviceSupport/<...>/Symbols/usr/lib/dyld

instead of just:

  /usr/lib/dyld

This makes the test pass when running against an embedded Darwin device.