Removed a <?> generic in a instanceof.

This syntax is broken under Eclipse.
For some reason this syntax is valid from BuildJar
but it is not compatible with Eclipse Java 8.

--
MOS_MIGRATED_REVID=89397040

src/main/java/com/google/devtools/build/lib/packages/RawAttributeMapper.java

@@ -66,7 +66,7 @@ protected <T> Iterable<T> visitAttribute(String attributeName, Type<T> type) {
    */
   @Nullable
   public <T> Collection<T> getMergedValues(String attributeName, Type<List<T>> type) {
-    Preconditions.checkState(type instanceof Type.ListType<?>);
+    Preconditions.checkState(type instanceof Type.ListType);
     if (!isConfigurable(attributeName, type)) {
       return get(attributeName, type);
     }