x/tools/go/ssa: Accept struct conversions that ignore tags

This is now allowed in go1.8.

Fixes golang/go#19646.

Change-Id: Iece4fd2a881144bdbe841e0a26ba4348d6b8828e
Reviewed-on: https://go-review.googlesource.com/38452
Reviewed-by: Alan Donovan <adonovan@google.com>
Run-TryBot: Alan Donovan <adonovan@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
6 files changed