Memory mode: Adding support for synchronous instruments - Last Value aggregation

[asafm]

Epic

This is one of many PRs that implement #5105. See the complete plan here.
Specifically, this PR adds the implementation of MemoryMode for the synchronous instrument: counter.

What was done here?

This PR adds support for Memory mode for Last Value Aggregation. It contains:

• Using a reusable point for returning the result on doAggregateThenMaybeReset for both LongLastValueAggregator.Handle and DoubleLastValueAggregator.Handle.
• Adding matching garbage collection benchmark tests
• Adjusting and adding tests for LongLastValueAggregator and DoubleLastValueAggregator

[asafm]

@jack-berg Last aggregator 🎉

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (eba8b84) 91.06% compared to head (7dec3a9) 91.04%.
Report is 12 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@ ## main #6196 +/- ## ============================================ - Coverage 91.06% 91.04% -0.02%  - Complexity 5672 5678 +6  ============================================ Files 620 621 +1 Lines 16560 16603 +43 Branches 1690 1698 +8 ============================================ + Hits 15080 15116 +36  - Misses 993 996 +3  - Partials 487 491 +4 

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