Added support for Android checks

using the publicly available Maven library 'android.jar' (and
experimental:android_runtime for our internal version). Deleted the
handwritten Android stubs.

RELNOTES: N/A
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=114345338

core/pom.xml

@@ -196,6 +196,20 @@
       <version>56.1</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <!-- Apache 2.0 -->
+      <groupId>com.google.android</groupId>
+      <artifactId>android</artifactId>
+      <version>4.1.1.4</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <!-- Apache 2.0 -->
+      <groupId>com.google.android</groupId>
+      <artifactId>support-v4</artifactId>
+      <version>r6</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
   <build>

core/src/test/java/com/google/errorprone/bugpatterns/android/MislabeledAndroidStringTest.java

@@ -85,7 +85,7 @@ public void testNegativeCase() throws Exception {
             "import android.R;",
             "public class FineStringTest {",
             "  public int getStringId() {",
-            "    return R.string.maybe;",
+            "    return R.string.copy;",
             "  }",
             "}")
         .doTest();
@@ -104,18 +104,6 @@ public void testAssumedMeanings() throws Exception {
   }
 
   private CompilationTestHelper createCompilationTestHelper() {
-    // Use fake android.R class to avoid compile-time dependency on Android
-    return
-        CompilationTestHelper
-            .newInstance(MislabeledAndroidString.class, getClass())
-            .addSourceLines("android/R.java",
-                "package android;",
-                "public final class R {",
-                "  public static final class string {",
-                "    public static final int yes = -1;",
-                "    public static final int no = -2;",
-                "    public static final int maybe = -3;",
-                "  }",
-                "}");
+    return CompilationTestHelper.newInstance(MislabeledAndroidString.class, getClass());
   }
 }

core/src/test/java/com/google/errorprone/bugpatterns/android/RectIntersectReturnValueIgnoredTest.java

@@ -34,8 +34,6 @@ public class RectIntersectReturnValueIgnoredTest {
   public void setUp() {
     compilationHelper =
         CompilationTestHelper.newInstance(RectIntersectReturnValueIgnored.class, getClass());
-    compilationHelper.addSourceFile("stubs/android/graphics/Rect.java");
-
   }
 
   @Test