Revoke existing end user oAuth 2.0 access tokens/refresh token using management API call

[lintu_cherian]

@dchiesa1  @anilsagar 

We have a scenario where we have to clear sessions of few app users . We had used management api call oauth2/revoke?enduser=1xxxxx to revoke the tokens . but as observed if the access token is expired api calls cannot invalidate expired access token hence refresh token are alive. and we dont have api's to get the list of refresh token for this users. How could we revoke the refresh token for a few users where the access token is expired.