Enable io.netty.leakDetection.level=paranoid in tests

Issue: SPR-17574

Author: rstoyanchev

build.gradle

@@ -132,6 +132,7 @@ configure(allprojects) { project ->
 	test {
 		systemProperty("java.awt.headless", "true")
 		systemProperty("testGroups", project.properties.get("testGroups"))
+		systemProperty("io.netty.leakDetection.level", "paranoid")
 		scanForTestClasses = false
 		include(["**/*Tests.class", "**/*Test.class"])
 		// Since we set scanForTestClasses to false, we need to filter out inner