Allocate hash-based collections with sufficient capacity for expected size

The JDK API to create hash-based collections for a certain capacity is arguable misleading because it doesn't size the collections to "hold a specific number of items" like you'd expect it would. Instead it sizes it to hold load-factor% of the specified number.

For the common pattern to allocate a hash-based collection with the size of expected elements to avoid rehashes, this means that a rehash is essentially guaranteed.

We should introduce helper methods (similar to Guava's `Maps.newHashMapWithExpectedSize(int)`) for allocations for expected size and replace the direct constructor calls with those.