Suppress some rawtype and unchecked cast warnings.

In theory these should be fixed but that would require a non-trival redesign in some cases.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=251932243

src/com/google/javascript/jscomp/graph/Annotatable.java

@@ -31,8 +31,8 @@ public interface Annotatable {
   /**
    * Retrieves a piece of information that has been annotated.
    *
-   * @return The annotation or <code>null</code> if the object has not
-   *     been annotated.
+   * @return The annotation or <code>null</code> if the object has not been annotated.
    */
+  @SuppressWarnings("unchecked")
   <A extends Annotation> A getAnnotation();
 }

src/com/google/javascript/jscomp/transpile/CachingTranspiler.java

@@ -38,6 +38,7 @@ public final class CachingTranspiler implements Transpiler {
   private final LoadingCache<Key, TranspileResult> cache;
   private final Supplier<String> runtime;
 
+  @SuppressWarnings("unchecked")
   public CachingTranspiler(
       final Transpiler delegate, CacheBuilder<Object, ? super TranspileResult> builder) {
     checkNotNull(delegate);

test/com/google/javascript/jscomp/CompilerTestCase.java

@@ -1650,7 +1650,7 @@ private void testInternal(
               .that(externsDifference.entriesDiffering())
               .isEmpty();
 
-          MapDifference sourceDifference =
+          MapDifference<String, PropertyAccessKind> sourceDifference =
               Maps.difference(
                   compiler.getSourceGetterAndSetterProperties(),
                   GatherGettersAndSetterProperties.gather(compiler, mainRoot));