run synctest with Go 1.25

.github/actions/go-test-setup/action.yml

@@ -9,10 +9,10 @@ runs:
       shell: bash
       # This matches only tests with "NoCover" in their test name to avoid running all tests again.
       run: go test -tags nocover -run NoCover -v ./...
-    - name: Run synctests tests. These are tests that require go 1.24 and the experimental testing/synctest package
+    - name: Run synctests tests. These are tests that require go 1.25 and the experimental testing/synctest package
       shell: bash
-      if: ${{ contains(matrix.go, '1.24') }}
-      run: go test -tags goexperiment.synctest -run "_synctest$" -v ./...
+      if: ${{ contains(matrix.go, '1.25') }}
+      run: go test -run "_synctest$" -v ./...
     - name: Install testing tools
       shell: bash
       run: cd scripts/test_analysis && go install ./cmd/gotest2sql

x/simlibp2p/synctest_test.go

@@ -1,4 +1,4 @@
-//go:build goexperiment.synctest
+//go:build go1.25
 
 package simconnlibp2p_test
 
@@ -19,7 +19,7 @@ import (
 )
 
 func TestSimpleLibp2pNetwork_synctest(t *testing.T) {
-	synctest.Run(func() {
+	synctest.Test(t, func(t *testing.T) {
 		latency := 10 * time.Millisecond
 		network, meta, err := simlibp2p.SimpleLibp2pNetwork([]simlibp2p.NodeLinkSettingsAndCount{
 			{LinkSettings: simnet.NodeBiDiLinkSettings{