Remove broken tests

1) removed old, unused, and broken MmsReceiverTest.
2) removed RegistrationActivityTest which got entirely broken
   when 8573316fdf removed the
   Class it inherited from (RoutedInstrumentationTestCase).

all tests in connectedCheck target now passing on Nexus One
 GB test device.

Closes #2864

// FREEBIE

androidTest/java/org/thoughtcrime/securesms/RegistrationActivityTest.java

@@ -1,24 +0,0 @@
-package org.thoughtcrime.securesms;
-
-import static android.support.test.espresso.Espresso.*;
-import static android.support.test.espresso.action.ViewActions.*;
-import static android.support.test.espresso.matcher.ViewMatchers.*;
-import static android.support.test.espresso.assertion.ViewAssertions.*;
-
-import android.test.suitebuilder.annotation.LargeTest;
-
-@LargeTest
-public class RegistrationActivityTest extends RoutedInstrumentationTestCase {
-  private final static String TAG = RegistrationActivityTest.class.getSimpleName();
-
-  public RegistrationActivityTest() {
-    super();
-  }
-
-  @SuppressWarnings("unchecked")
-  public void testRegistrationButtons() throws Exception {
-    waitOn(RegistrationActivity.class);
-    onView(withId(R.id.registerButton)).check(matches(isDisplayed()));
-    onView(withId(R.id.skipButton)).check(matches(isDisplayed())).perform(click());
-  }
-}

androidTest/org/thoughtcrime/securesms/service/MmsReceiverTest.java

@@ -1,28 +0,0 @@
-package org.thoughtcrime.securesms.service;
-
-import android.content.Intent;
-import android.test.InstrumentationTestCase;
-
-import static org.fest.assertions.api.Assertions.*;
-
-public class MmsReceiverTest extends InstrumentationTestCase {
-
-  private MmsReceiver mmsReceiver;
-
-  public void setUp() throws Exception {
-    super.setUp();
-    mmsReceiver = new MmsReceiver(getInstrumentation().getContext());
-  }
-
-  public void tearDown() throws Exception {
-
-  }
-
-  public void testProcessMalformedData() throws Exception {
-    Intent intent = new Intent();
-    intent.setAction(SendReceiveService.RECEIVE_MMS_ACTION);
-    intent.putExtra("data", new byte[]{0x00});
-    mmsReceiver.process(null, intent);
-  }
-
-}