patch 9.1.0027: Vim is missing a foreach() func

patch 9.1.0027: Vim is missing a foreach() func

Problem:  Vim is missing a foreach() func
Solution: Implement foreach({expr1}, {expr2}) function,
          which applies {expr2} for each item in {expr1}
          without changing it (Ernie Rael)

closes: #12166

Signed-off-by: Ernie Rael <errael@raelity.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>