Add Java API to exclude groups for reviewer suggestion

Use the new API to test exclusion of groups for reviewer suggestion.

Change-Id: I1b6456e09c5f1d8ae3dc7870976f8e3757088163
Signed-off-by: Edwin Kempin <ekempin@google.com>

java/com/google/gerrit/server/api/changes/ChangeApiImpl.java

@@ -448,6 +448,7 @@ class ChangeApiImpl implements ChangeApi {
     try {
       suggestReviewers.setQuery(r.getQuery());
       suggestReviewers.setLimit(r.getLimit());
+      suggestReviewers.setExcludeGroups(r.getExcludeGroups());
       return suggestReviewers.apply(change).value();
     } catch (Exception e) {
       throw asRestApiException("Cannot retrieve suggested reviewers", e);