[dev.regabi] cmd/compile: simplify export data representation of nil
The handling of ONIL and Orig has been a mess for a while, and dates
back to how fmt.go used to print out typed nils. That hasn't applied
for a while, but we've kept dragging it along to appease toolstash
with the intention of someday finally removing it.
Today is that day.
Change-Id: I9a441628e53068ab1993cd2b67b977574d8117b7
Reviewed-on: https://go-review.googlesource.com/c/go/+/274212
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com> Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>