Windows: Add missing quotes in build file

All invokations of $(PERL) need to be quoted, in case it contains
spaces.  That was forgotten in one spot.

Fixes #9060

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/9062)