gcov analysis showed that none of the actual testing conditions were hit, so
the test succeeded despite not actually testing anything. Which is good,
because testing for tilt normalization isn't correct anyway, tilt is in
physical degrees,

Drop the test and replace it with a test for pressure normalization instead.
We already have a similar one to check for [0, 1] range, this new one
explicitly tests for the extents.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>