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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