Merge pull request rails#6667 from yahonda/skip_polymorphic_index_with_oracle

Skip two tests with polymorphic if current adapter is Oracle Adapter.

Author: rafaelfranca

activerecord/test/cases/migration/references_index_test.rb

@@ -51,6 +51,8 @@ def test_creates_index_with_options
       end
 
       def test_creates_polymorphic_index
+        return skip "Oracle Adapter does not support foreign keys if :polymorphic => true is used" if current_adapter? :OracleAdapter
+
         connection.create_table table_name do |t|
           t.references :foo, :polymorphic => true, :index => true
         end
@@ -86,6 +88,7 @@ def test_does_not_create_index_for_existing_table_explicit
       end
 
       def test_creates_polymorphic_index_for_existing_table
+        return skip "Oracle Adapter does not support foreign keys if :polymorphic => true is used" if current_adapter? :OracleAdapter
         connection.create_table table_name
         connection.change_table table_name do |t|
           t.references :foo, :polymorphic => true, :index => true