Fix setting of success in Socket::Close()

[shafik]

Summary

Both close and closesocket should return 0 on success so using !! looks incorrect. I replaced this will a more readable == 0 check.

[shafik]

AFAICT this fix is correct but I am not sure how to verify of test it. I ran the test suite and it passed but that does not mean this is being covered.

[labath]

Usually, the only thing one can do if a close fails is to log an error message, so it's not completely surprising that this has gone by unnoticed.

It might be nice to insert a close call to one of the existing Socket unit tests (or add a new one), but other than that, I am pretty sure this is fine.

lldb/source/Host/common/Socket.cpp

Status Socket::Close() {
   if (!IsValid() || !m_should_close_fd)
     return error;
 
   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION));
   LLDB_LOGF(log, "%p Socket::Close (fd = %" PRIu64 ")",
             static_cast<void *>(this), static_cast<uint64_t>(m_socket));
 
 #if defined(_WIN32)
-  bool success = !!closesocket(m_socket);
+  bool success = closesocket(m_socket) == 0;
 #else
-  bool success = !!::close(m_socket);
+  bool success = ::close(m_socket) == 0;
 #endif
   // A reference to a FD was passed in, set it to an invalid value
   m_socket = kInvalidSocketValue;
   if (!success) {
     SetLastError(error);
   }
 
   return error;