The problem in callnk.cxx was that when selecting 1 char to the right
using keyboard, and exiting field boundary, nCmp pointed to previous
position (inside field), and then compared to position to the left
(which also may be inside field), thus missing call change link (and
read-only state change). Seems that this was a mistake in commit
740efbb1.

In pam.cxx, if cursor was to the left of field, and then selected
1 char to the right to cross field's boundary, then both PaM's point
and mark had same fieldmark, but point was outside, and mark inside,
and as code didn't check this condition, so read-only state wasn't
properly set.

Unit test is augmented to check the second problem.

Change-Id: I7323e53eeb261b4ccdc0f9e36cc0956b373f104d
Reviewed-on: https://gerrit.libreoffice.org/33790Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>