(line-move-1): Obey `inhibit-point-motion-hooks`

(line-move-1): Obey `inhibit-point-motion-hooks`

`line-move-1` was written back before `inhibit-point-motion-hooks`
was made obsolete and it's written under the assumption that its
value is nil, whereas since Emacs-25 it's t.

To work around problems linked to a nil value of
`inhibit-point-motion-hooks`, the code temporarily binds that var to
t while it moves around trying to find the final destination and then
later in a few key spots it binds it "back" to nil so as to run the
point-motion hooks according to the final destination, as if the
overall motion had been made "normally".

Change the code so that the "bind back" indeed binds the var back to
the value it had originally, rather than always to nil.

* lisp/simple.el (line-move-1): Obey `inhibit-point-motion-hooks`
(line-move-finish): New optional arg `not-ipmh`.