Factorize custom asserts.

Also a few utilities that were in the way, and some opportunistic
cleanups.

Test: FrameworksNetTest NetworkStackTest
Change-Id: I385070e2044fd967cb18f1ffea9a86a4627b742e

tests/net/java/android/app/usage/NetworkStatsManagerTest.java

@@ -202,8 +202,7 @@ public class NetworkStatsManagerTest {
         assertFalse(stats.hasNextBucket());
     }
 
-    private void assertBucketMatches(Entry expected,
-            NetworkStats.Bucket actual) {
+    private void assertBucketMatches(Entry expected, NetworkStats.Bucket actual) {
         assertEquals(expected.uid, actual.getUid());
         assertEquals(expected.rxBytes, actual.getRxBytes());
         assertEquals(expected.rxPackets, actual.getRxPackets());