Go vendor update

vendor/github.com/cespare/xxhash/v2/testall.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+set -eu -o pipefail
+
+# Small convenience script for running the tests with various combinations of
+# arch/tags. This assumes we're running on amd64 and have qemu available.
+
+go test ./...
+go test -tags purego ./...
+GOARCH=arm64 go test
+GOARCH=arm64 go test -tags purego