promqltest: Complete the tests for info annotations
So far, we did not test for the _absence_ of an info annotation
(because many tests triggered info annotations, which we haven't taken
into account so far).
The test for info annotations was also missed for range queries.
This completes the tests for info annotations (and refactors the many
`if` statements into a somewhat more compact `switch` statement).
It fixes most tests to not emit an info annotation anymore. Or it
changes the `eval` to `eval_info` where we actually want to test for
the info annotation.
It also fixes a few spelling errors in comments.
---------
Signed-off-by: beorn7 <beorn@grafana.com>
Signed-off-by: Björn Rabenstein <github@rabenste.in>
Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>
