Use test context in tests and new loop system in benchmarks (#33648)

Replace all contexts in tests with go1.24 t.Context()

---------

Co-authored-by: Giteabot <teabot@gitea.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/auth/oauth2_test.go

@@ -25,7 +25,7 @@ func TestOAuth2Application_GenerateClientSecret(t *testing.T) {
 func BenchmarkOAuth2Application_GenerateClientSecret(b *testing.B) {
 	assert.NoError(b, unittest.PrepareTestDatabase())
 	app := unittest.AssertExistsAndLoadBean(b, &auth_model.OAuth2Application{ID: 1})
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		_, _ = app.GenerateClientSecret(db.DefaultContext)
 	}
 }