[lldb] Remove unused Socket::PreDisconnect (NFC)

lldb/include/lldb/Host/Socket.h

@@ -93,7 +93,6 @@ public:
   Status Read(void *buf, size_t &num_bytes) override;
   Status Write(const void *buf, size_t &num_bytes) override;
 
-  virtual Status PreDisconnect();
   Status Close() override;
 
   bool IsValid() const override { return m_socket != kInvalidSocketValue; }

lldb/source/Host/common/Socket.cpp

@@ -269,11 +269,6 @@ Status Socket::Write(const void *buf, size_t &num_bytes) {
   return error;
 }
 
-Status Socket::PreDisconnect() {
-  Status error;
-  return error;
-}
-
 Status Socket::Close() {
   Status error;
   if (!IsValid() || !m_should_close_fd)

lldb/source/Host/posix/ConnectionFileDescriptorPosix.cpp

@@ -202,9 +202,6 @@ ConnectionStatus ConnectionFileDescriptor::Disconnect(Status *error_ptr) {
     return eConnectionStatusSuccess;
   }
 
-  if (m_io_sp->GetFdType() == IOObject::eFDTypeSocket)
-    static_cast<Socket &>(*m_io_sp).PreDisconnect();
-
   // Try to get the ConnectionFileDescriptor's mutex.  If we fail, that is
   // quite likely because somebody is doing a blocking read on our file
   // descriptor.  If that's the case, then send the "q" char to the command