Fix WASM build

Constant used by WASM+Go tests was in Go only file

agent_test.go

@@ -24,8 +24,6 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-const localhostIPStr = "127.0.0.1"
-
 type BadAddr struct{}
 
 func (ba *BadAddr) Network() string {

candidate_test.go

@@ -13,6 +13,8 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+const localhostIPStr = "127.0.0.1"
+
 func TestCandidateTypePreference(t *testing.T) {
 	r := require.New(t)