YT-22382: Misra-Gries heavy hitters acceleration

Using refs in internal structures in MisraGriesHeavyHitters for acceleration and less memory consumption.

This give improvements from:

```
----------------------------------------------------------------------------------------------
Benchmark                                                    Time             CPU   Iterations
----------------------------------------------------------------------------------------------
HeavyHittersBenchmark/SingleIntSchema/iterations:20        591 ms          591 ms           20
HeavyHittersBenchmark/UrlDataSchema/iterations:20         1460 ms         1460 ms           20
```

To:

```
----------------------------------------------------------------------------------------------
Benchmark                                                    Time             CPU   Iterations
----------------------------------------------------------------------------------------------
HeavyHittersBenchmark/SingleIntSchema/iterations:20        558 ms          558 ms           20
HeavyHittersBenchmark/UrlDataSchema/iterations:20         1020 ms         1020 ms           20
```

This is an acceleration of more than 1.4 times on the benchmark with complex schema. On the benchmark with schema consisting of a single ui64 there is also a slight acceleration.
commit_hash:b854f0a0182da0f5f8a3c9b9db8f267f177885db

0 files changed, 0 insertions, 0 deletions