[json] Use S.R.I vectors in JsonReaderHelper (#81758)

[json] Use S.R.I vectors in JsonReaderHelper (#81758)

* [json] Use S.R.I vectors in JsonReaderHelper

wasm performance improvement

| measurement | new simd | old simd | nosimd |
|-:|-:|-:|-:|
|       Json, non-ASCII text deserialize |     0.4234ms |     0.4280ms |     0.4234ms |
|                Json, small deserialize |     0.0376ms |     0.0402ms |     0.0397ms |
|                Json, large deserialize |    10.4231ms |    11.1614ms |    11.0021ms |

microbenchmarks perf

    --filter *Text.Json*Read*
    summary:
    better: 170, geomean: 1.120
    worse: 15, geomean: 1.080
    total diff: 185

* Use SRI vectors only on net7 and later