tests/lint: sort multiple diagnostics per line chronologically

For now, the chronologic order is not enforced but has to be established
manually, for example by removing all 'expect' comment lines and
regenerating them with 'accept.sh -u'.

While here, clean up a few instances that came up when regenerating the
'expect' comments, such as wrong indentation or needless deviation from
the 'expect+1' form.

lint: fix type of large integer constants

tests/lint: test integer constants in different language levels