When an OAS node is converted to an OSELRECV2 node in tcSelect(), the
possible DCL node in the Init field was being dropped, since a
completely new node was being created and the Init field was not set. I
don't expect n.Init() to be set for the ORECV case, but the code now
deals with that too.
Fixed bug in both tcSelect() and transformSelect().
Cherry-picked from https://go-review.googlesource.com/c/go/+/348569Fixes#49511
Change-Id: Id5b736daa8e90afda88aaa3769dde801db294c0d
Reviewed-on: https://go-review.googlesource.com/c/go/+/363664
Trust: Dan Scales <danscales@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>