dashboard: only run misc-vet-vetall for master

As of CL 169198 for golang/go#31040, the coordinator no longer supports
placing the x/tools files out for Go 1.11 and Go 1.12's cmd/vet/all to
find, so their misc-vet-vetall builds will start failing.

We could in theory still either backport CL 169237 to
release-branch.go1.11 and release-branch.go1.12, and/or we could keep
running the misc-vet-vetall builder for the future Go 1.13 release
branch, but it's not obviously even worth it; the vetall builder is
most useful during development anyway. The tree is pretty stable once
it's release branch time. The main use of misc-vet-vetall is catching
assembly vet failures (since go test now does most the other vet
checks), and assembly doesn't often change in release branches.

Updates golang/go#31040

Change-Id: I7b827ecbcd206f3dcf63e04cc94fb78854befd7d
Reviewed-on: https://go-review.googlesource.com/c/build/+/169339
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
diff --git a/dashboard/builders_test.go b/dashboard/builders_test.go
index 5d7ec5f..03eff19 100644
--- a/dashboard/builders_test.go
+++ b/dashboard/builders_test.go
@@ -122,7 +122,6 @@
 				"misc-compile-openbsd",
 				"misc-compile-plan9",
 				"misc-compile-ppc",
-				"misc-vet-vetall",
 				"nacl-386",
 				"nacl-amd64p32",
 				"openbsd-amd64-64",
@@ -266,6 +265,10 @@
 		{b("linux-amd64", "net"), both},
 		{b("linux-amd64", "sys"), both},
 
+		{b("misc-vet-vetall", "go"), both},
+		{b("misc-vet-vetall@go1.11", "go"), none},
+		{b("misc-vet-vetall@go1.12", "go"), none},
+
 		// Don't test all subrepos on all the builders.
 		{b("linux-amd64-ssacheck", "net"), none},
 		{b("linux-amd64-ssacheck@go1.10", "net"), none},