Simplify 'with-restriction' and 'without-restriction'

Simplify 'with-restriction' and 'without-restriction'

* lisp/subr.el (with-restriction, without-restriction): Merge the
bodies of the 'internal--with-restriction' and
'internal--without-restriction' function into the macros.  The
result is more efficient than a funcall.
(internal--with-restriction, internal--without-restriction):
Remove.
Suggested by Mattias Engdegård.