SubscriptionManager: Cache created resources

Optimize resource handling in SubscriptionManager by caching
Resources created in getResourcesForSubId.

Inspired by commit: f9a7ccc1be43459516f0df0fc7042b1bc0560dd2

Bug: 144051856
Test: Manual
Change-Id: Id6878f933f09f9e3df183ffe45bf60108038889d
1 file changed