Convert ConnectivityCheckerTestBase children to JUnit4

For more on JUnit4 migration, please check src/testing/android/docs/junit4.md

BUG=640116

Review-Url: https://codereview.chromium.org/2878203002
Cr-Commit-Position: refs/heads/master@{#471930}
diff --git a/chrome/android/java_sources.gni b/chrome/android/java_sources.gni
index 3c5799f7..86de6433 100644
--- a/chrome/android/java_sources.gni
+++ b/chrome/android/java_sources.gni
@@ -1399,7 +1399,7 @@
   "javatests/src/org/chromium/chrome/browser/externalnav/IntentWithGesturesHandlerTest.java",
   "javatests/src/org/chromium/chrome/browser/externalnav/UrlOverridingTest.java",
   "javatests/src/org/chromium/chrome/browser/feedback/ConnectivityCheckerTest.java",
-  "javatests/src/org/chromium/chrome/browser/feedback/ConnectivityCheckerTestBase.java",
+  "javatests/src/org/chromium/chrome/browser/feedback/ConnectivityCheckerTestRule.java",
   "javatests/src/org/chromium/chrome/browser/feedback/ConnectivityTaskTest.java",
   "javatests/src/org/chromium/chrome/browser/feedback/FeedbackCollectorTest.java",
   "javatests/src/org/chromium/chrome/browser/firstrun/FirstRunActivityTestObserver.java",