/usr/share/go-1.8/test/goprint.out is in golang-1.8-src 1.8.3-2ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1
42 true false true +1.500000e+000 world 0x0 [0/0]0x0 0x0 0x0 255