The vetall builder runs vet straight out of golang.org/x/tools,
so submiting CL 176097 in that repo will break the builder
by making all these whitelist entries stale.
Submiting this CL will fix it, by removing them.

The addition of the gcWriteBarrier declaration in runtime/stubs.go
is necessary because the diagnostic is no longer emitted on arm,
so it must be removed from all.txt. Adding it to runtime is better
than adding it to every-other-goarch.txt.

For #31916.

Change-Id: I432f6049cd3ee5a467add5066c440be8616d9d54
Reviewed-on: https://go-review.googlesource.com/c/go/+/176177
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>