Fix broken max macro on Windows

[Kerisa]

Hi there,

I found that if I include the auto generated XX.pb.h in my code then the "max" macro defined by Windows will be broken.

And this is caused by a direct undef in src/google/protobuf/arena.h

#ifdef max
#undef max  // Visual Studio defines this macro
#endif

I think this should be done by using port_def.inc and port_undef.inc pairs so I removed this undef and add a protect on src/google/protobuf/stubs/stl_util.h.

Thank you

[Kerisa]

I have sign the Google Individual CLA agreement just now, is there any one who can help to trigger a rescan? Thanks.