Avoid Object2LongMap.Entry allocations

[embeddedt]

Small tweaks to reduce the number of entries that get allocated on each server tick when updating the cached stacks.

A number of remaining allocations here appear to be from

Applied-Energistics-2/src/main/java/appeng/api/stacks/VariantCounter.java

Line 95 in 126ff28

return getRecords().object2LongEntrySet().iterator();

. Ideally that should use Object2LongMaps.fastIterator, but I am not sure if doing so is safe, since I'm not familiar with the rest of the code.

[shartte]

I checked all iterable uses of KeyCounter and found no case where its entry was in some way stored outside of the for-loop. I think we're good with using the fast entry set there too. Addons may do it, but I doubt it.