Opt18R: MVC: Rename PathHelpers to UrlUtil.
Opt19: ValueProviderResultPlaceholder: reduce allocations of Lazy and delegate instances.
Opt20: BrowserHelpers: Avoid per-call creation of delegate instances.
Opt21: MVC: Remove Lazy and delegates from action descriptors.
Opt22: WebPages: FileExistenceCache eliminate per call delegate creation.
Opt24: MVC: ActionMethodDispatcherCache: Prevent per-call allocation with static inline delegate.