cmd/compile: fix compilation crash with several blank labels
Fixes #52278
Change-Id: Ibf67c7b019feec277d316e04d93b458efea133fb
Reviewed-on: https://go-review.googlesource.com/c/go/+/399574 Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org> Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Keith Randall <khr@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com>