client-tokens - memory db returns client createdAt instead of token createdAt

[vladikoff]

Ref: Memory https://github.com/mozilla/fxa-oauth-server/blob/master/lib/db/memory.js#L256

Ref: SQL

fxa-oauth-server/lib/db/mysql/index.js

Lines 180 to 188 in 5cdf36b

	// Token management by uid.
	// Returns the most recent token used with a client name and client id.
	// Does not include clients that canGrant.
	const QUERY_ACTIVE_CLIENT_TOKENS_BY_UID =
	'SELECT DISTINCT clients.name, clients.id, MAX(tokens.createdAt) as createdAt FROM clients, tokens ' +
	'WHERE tokens.expiresAt > NOW() AND clients.canGrant = 0 AND clients.id = tokens.clientId AND tokens.userId=? ' +
	'GROUP BY id ' +
	'ORDER BY createdAt DESC, clients.name ' +
	'LIMIT 10000;';

We use MAX(tokens.createdAt) to sort by newest token in MySQL, but we just pick up .createdAt field in the memory db.