Make verify-typecheck not depend on GOPATH

This script fails if not under a GOPATH because we use go/types, which
is not modules aware.

Author: thockin

hack/verify-typecheck.sh

@@ -30,8 +30,13 @@ cd "${KUBE_ROOT}"
 
 make --no-print-directory -C "${KUBE_ROOT}" generated_files
 
+# As of June, 2020 the typecheck tool is written in terms of go/types, but that
+# library doesn't work well with modules.  Guidance is to rewrite tools against
+# golang.org/x/tools/go/packages.  Until that is done, force this tooling to
+# run in a fake GOPATH.
 ret=0
-go run test/typecheck/main.go "$@" || ret=$?
+hack/run-in-gopath.sh \
+    go run test/typecheck/main.go "$@" || ret=$?
 if [[ $ret -ne 0 ]]; then
   echo "!!! Type Check has failed. This may cause cross platform build failures." >&2
   echo "!!! Please see https://git.k8s.io/kubernetes/test/typecheck for more information." >&2