testament: line spec silently ignored in tests where errormsg is not specified

[timotheecour]

Example

in tests/init/tuninit1.nim:

discard """
  nimout: "Warning: use explicit initialization of 'y' for clarity [Uninit]"
  line:34
  action: compile
"""
...

change line:34 to line:1234

Current Output

test still passes

Expected Output

give error saying that line is ignored in presence of nimout and shouldn't be specified.

note also that specifying line and col and errormsg is IMO bad (because it's more work), instead, the test should specify if there's an error by adding relevant line to nimout, eg:

twrongcolon.nim(11, 12) Error: in expression ' do:

=> less work and less maintenance (just copy paste error)
=> test is in no way weaker

Additional Information

• 1.5.1 fe7a76f
• found while reviewing fix #16693: testament spec nimout too lax #16698

EDIT: line is honored when errormsg is specified, and silently ignored when errormsg is not specified.
See #17643 (comment) for more details on this and for suggested fix.