Go 1.21 Upgrade

Fixes #11351

tpl/internal/go_templates/testenv/testenv_notunix.go

@@ -2,12 +2,19 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build windows || plan9 || (js && wasm)
+//go:build windows || plan9 || (js && wasm) || wasip1
 
 package testenv
 
-import "os"
+import (
+	"os"
+)
 
 // Sigquit is the signal to send to kill a hanging subprocess.
 // On Unix we send SIGQUIT, but on non-Unix we only have os.Kill.
 var Sigquit = os.Kill
+
+func syscallIsNotSupported(err error) bool {
+	// Removed by Hugo (not supported in Go 1.20).
+	return false
+}