Should Not Cache With Multiple Max-Age

[akrambek]

According to

When there is more than one value present for a given directive
   (e.g., two Expires header fields, multiple Cache-Control: max-age
   directives), the directive's value is considered invalid.  Caches are
   encouraged to consider responses that have invalid freshness
   information to be stale.

Currently it throws an execption causing the feature to misbehave.

To reproduce the issue run Rfc7234ProxyIT.shouldNotCacheWithMultipleMaxAge IT.