/usr/bin/lldb-gdbserver-3.5 is in lldb-3.5 1:3.5-4ubuntu2~trusty2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/../lib/llvm-3.5/bin/lldb-gdbserver
/usr/bin/../lib/llvm-3.5/bin/lldb-gdbserver