[minor] fix Gradle test broken on the build refactoring

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/new-model-in-old-plugin/build.gradle.kts

@@ -40,7 +40,7 @@ kotlin.target.compilations {
     }
 }
 
-val runBenchmark by tasks.registering<JavaExec> {
+val runBenchmark by tasks.registering(JavaExec::class) {
     classpath = kotlin.target.compilations["benchmark"].run { runtimeDependencyFiles + output.allOutputs }
     main = "com.example.ABenchmarkKt"
 }