tests: fix shuf test verifying that -i and -e can not be combined

tests: fix shuf test verifying that -i and -e can not be combined

Previously, the test triggered another error diagnostic:
  shuf: invalid input range ‘-e’
and therefore eclipsed the expected one:
  shuf: cannot combine -e and -i options

While at it, reindent a line with more than 80 characters, present
since the previous commit to silence sc_long_lines.

* tests/misc/shuf.sh: Pass a valid range to the -i option.