When we add a view, we should check if we already have a view for the
given folder.
Updates golang/go#48844
Change-Id: I0de27d420e2b4df3b33b913ae27b108bab6b7d12
Reviewed-on: https://go-review.googlesource.com/c/tools/+/356933
Trust: Rebecca Stambler <rstambler@golang.org>
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Go Bot <gobot@golang.org>