Implement `JsonNoCanonicalizeReadVanilla`

[carterkozak]

This benchmark class is equivalent to JsonStdReadVanilla but disables CANONICALIZE_FIELD_NAMES.

I don't have much preference whether this is merged, I can see an argument that this variant is already covered by covered by JsonArbitraryFieldNameBenchmark instead, but I prefer to share benchmarking code when I share results.