plive doesn't like the fact that we put JMPs right
after CALL ops to select{send,recv}.

Fixes SSA -N build.

Change-Id: I9b3c9e5293196094fd5a6206dd2f99784951f7a9
Reviewed-on: https://go-review.googlesource.com/19982
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>