Deparse list repetition assignment properly

Deparse list repetition assignment properly

This only applies to the almost useless case of nothing but a repetition
on the lhs of list assignment:  ((undef)x3) = foo();

Other cases where the repetition is part of a larger list already
deparsed correctly.

Checking whether the lhs begins with a parenthesis is not sufficient
to determine whether the lhs is parenthesized.  I believe repetition
is the only binary op other than the comma that is allowed on the
lhs, so we can just check for that in the op tree.