Performance regressions found in Brotli v1.1.0

The [dotnet/runtime](https://github.com/dotnet/runtime) repo recently [updated](https://github.com/dotnet/runtime/pull/107102/files) its in-tree copy of its Brotli dependency from [v1.0.9](https://github.com/google/brotli/releases/tag/v1.0.9) to [v1.1.0](https://github.com/google/brotli/releases/tag/v1.1.0).

We ran our performance benchmarks, and we noticed regressions in [Linux-x64](https://github.com/dotnet/perf-autofiling-issues/issues/40587) and [Windows-x64](https://github.com/dotnet/runtime/issues/107302).

Most of our regression results were under **15%**, but 6 results were between **39%** an **49%**.

Here's a list of the tests that showed regressions:

#### Windows x64

- 49% - Decompress_WithState(level: Fastest, file: "TestDocument.pdf")
- 47% - Decompress_WithState(level: Optimal, file: "TestDocument.pdf")
- 47% - Decompress_WithoutState(level: Fastest, file: "TestDocument.pdf")
- 47% - Decompress_WithoutState(level: Optimal, file: "TestDocument.pdf")
- 39% - Decompress(level: Fastest, file: "TestDocument.pdf")
- 39% - Decompress(level: Optimal, file: "TestDocument.pdf")
- 13% - Decompress_WithoutState(level: Fastest, file: "alice29.txt")
- 12% - Decompress_WithoutState(level: Optimal, file: "alice29.txt")
- 12% - Decompress_WithState(level: Fastest, file: "alice29.txt")
- 11% - Decompress_WithState(level: Optimal, file: "alice29.txt")
- 11% - Decompress(level: Fastest, file: "alice29.txt")
- 10% - Decompress(level: Optimal: file: "alice29.txt")
- 10% - Decompress_WithState(level: Fastest, file: "sum")
- 10% - Decompress_WithoutState(level: Fastest, file: "sum")
- 09% - Decompress(level: Fastest, file: "sum")

#### Linux x64

- 16% - Compress_WithoutState(level: Optimal, file: "TestDocument.pdf")
- 16% - Compress_WithState(level: Optimal, file: "TestDocument.pdf")
- 15% - Compress_WithoutState(level: Optimal, file: "alice29.txt")
- 15% - Compress_WithoutState(level: Optimal, file: "sum")
- 14% - Compress_WithState(level: Optimal, file: "sum")
- 13% - Compress_WithState(level: Optimal, file: "alice29.txt")

Some more info:

- Our benchmark methods can be found [here](https://github.com/dotnet/performance/blob/main/src/benchmarks/micro/libraries/System.IO.Compression/Brotli.cs
Files tested: https://github.com/dotnet/performance/tree/main/src/benchmarks/micro/libraries/System.IO.Compression/TestData).
- Our in-tree copy of Brotli v1.1.0 is found [here](https://github.com/dotnet/runtime/tree/release/9.0/src/native/external/brotli).
- The managed code that consumes the in-tree copy of Brotli can be found [here](https://github.com/dotnet/runtime/tree/release/9.0/src/libraries/System.IO.Compression.Brotli/src/System/IO/Compression).
- [These](https://github.com/dotnet/runtime/blob/a95d038411e80f07b5ef1264cc8425f55fbc5ec9/src/libraries/System.IO.Compression.Brotli/src/System/IO/Compression/BrotliUtils.cs) are the mappings of the `CompressionLevel` enum to Brotli quality values:
- "Fastest" => 1
- "Optimal" => 4:

Unfortunately, the [v1.1.0 tag](https://github.com/google/brotli/releases/tag/v1.1.0) has no mention of known perf regressions, so we were wondering if you were aware of these results and if you could help us figure out the possible root causes.