go/loader: normalize cycle to remove flake
go/loader: normalize cycle to remove flake

Fixes golang/go#31279

Change-Id: Idd1eead3b1e9a90ba39d04019ef32200deb4c983
Reviewed-on: https://go-review.googlesource.com/c/tools/+/185984
Run-TryBot: Michael Matloob <4562438b12c14e81a47550acde616ff328a909f8@golang.org>
Reviewed-by: Ian Cottrell <52376736e5e84615ec49f9c1843b8acc178b1d8d@google.com>

golang/tools,golang/tools,golang/tools,golang/tools,golang/tools