8013789: Compiler should emit bridges in interfaces

Paired with 8015402: Lambda metafactory should not attempt to determine bridge methods

Reviewed-by: vromero

langtools/test/tools/javac/lambda/methodReference/BridgeMethod.java

@@ -112,6 +112,6 @@ public class BridgeMethod {
             Class<?> returnType = m.getReturnType();
             assertTrue(types.remove(returnType.getName()));
         }
-        assertTrue(types.isEmpty());
+        assertTrue(types.size() == 1); //there's a bridge
     }
 }