One was OAPPEND of large types. We need to mem-mem copy them
instead of storing them.
Another was pointer-like struct and array types being put in the
data field of an eface. We need to use the underlying pointer
type for the load that fills in the eface.data field.
Change-Id: Id8278c0381904e52d59011a66ce46386b41b5521
Reviewed-on: https://go-review.googlesource.com/15552
Run-TryBot: Keith Randall <khr@golang.org> Reviewed-by: David Chase <drchase@google.com>