More generic type support for rapid implicits for scala 2.12

[jihoonson]

As suggested in #11307 (comment), we can make some rapid implicits more flexible by supporting more generic types, such as Iterable than SeqLike for safeClose(). This change will not only make it easier to use those APIs, but also make the caller implementation more efficient by avoiding unnecessary collection materializations.

[gerashegalov]

another benefit: we can reduce the degree of code divergence between Scala 2.12 and Scala 2.13