twitter-server: Fix flaky LoggingHandler test

Motivation

Due to the recent logging addition via TimerStats, depending on timing
this test sometimes sees different output.

Solution

Make the test more resilient to this sort of behavior.

RB_ID=743918

src/test/scala/com/twitter/server/handler/LoggingHandlerTest.scala

@@ -1,16 +1,16 @@
 package com.twitter.server.handler
 
-import com.twitter.finagle.httpx.{Request, Response, Status}
-import com.twitter.io.Charsets
+import com.twitter.finagle.httpx.{Request, Status}
 import com.twitter.logging.{Level, Logger}
-import com.twitter.server.util.HttpUtils._
 import com.twitter.util.Await
 import org.junit.runner.RunWith
-import org.scalatest.FunSuite
+import org.scalatest.{Matchers, FunSuite}
 import org.scalatest.junit.JUnitRunner
 
 @RunWith(classOf[JUnitRunner])
-class LoggingHandlerTest extends FunSuite {
+class LoggingHandlerTest extends FunSuite
+  with Matchers
+{
   test("query all loggers") {
     val handler = new LoggingHandler
     val loggers = Logger.iterator
@@ -61,7 +61,9 @@ class LoggingHandlerTest extends FunSuite {
       val res = Await.result(handler(req))
       assert(res.status === Status.Ok)
       val text = res.contentString
-      assert(text === "root OFF\nl0 ALL\nl1 DEBUG")
+      text should include ("root OFF")
+      text should include ("l0 ALL")
+      text should include ("l1 DEBUG")
     }
   }
 }