Migrate to Android Testing Support Lib (part 1/N)

This CL converts tests under com.android.inputmethod.latin.utils to
Android Testing Support Library.

Bug: 110805255
Test: verified as follows. No new test failures.
        tapas adb LatinIME LatinIMETests arm64 userdebug && \
        DISABLE_PROGUARD=true make -j LatinIME && \
        adb install -r $OUT/system/app/LatinIME/LatinIME.apk && \
        atest LatinIMETests:com.android.inputmethod.latin.utils
Change-Id: I5cc2ddbc4116003ab6407432ab521b6b560052ae
diff --git a/tests/src/com/android/inputmethod/latin/utils/JsonUtilsTests.java b/tests/src/com/android/inputmethod/latin/utils/JsonUtilsTests.java
index 1941120..e0a2b81 100644
--- a/tests/src/com/android/inputmethod/latin/utils/JsonUtilsTests.java
+++ b/tests/src/com/android/inputmethod/latin/utils/JsonUtilsTests.java
@@ -16,14 +16,23 @@
 
 package com.android.inputmethod.latin.utils;
 
+import static org.junit.Assert.assertEquals;
+
 import android.test.AndroidTestCase;
-import android.test.suitebuilder.annotation.SmallTest;
+import android.support.test.filters.SmallTest;
+import android.support.test.runner.AndroidJUnit4;
 
 import java.util.Arrays;
 import java.util.List;
 
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
 @SmallTest
-public class JsonUtilsTests extends AndroidTestCase {
+@RunWith(AndroidJUnit4.class)
+public class JsonUtilsTests {
+    @Test
     public void testJsonUtils() {
         final Object[] objs = new Object[] { 1, "aaa", "bbb", 3 };
         final List<Object> objArray = Arrays.asList(objs);