cmd/compile: fix load of interface{}-typed OpIData in expand_calls
In certain cases, the declkared type of an OpIData is interface{}.
This was not expected (since interface{} is a pair, right?) and
thus caused a crash. What is intended is that these be treated as
a byteptr, so do that instead (this is what happens in 1.15).
Fixes #42568.
Change-Id: Id7c9e5dc2cbb5d7c71c6748832491ea62b0b339f
Reviewed-on: https://go-review.googlesource.com/c/go/+/270057
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>