Improve JSON decoding speed by up to 40%

[mwylde]

Pulls in changes from apache/arrow-rs#7157 (rebased on our arrow-json fork as ArroyoSystems/arrow-rs@9cb387d4f55), which significantly improves JSON decoding performance.

This table shows performance improvements across various JSON documents (from ArroyoSystems/json-benchmarks):

Benchmark	BufIter (%)	memchr2 (%)	simdutf8 (%)	Total (%)
logs_json	-13.49%	-12.61%	-0.83%	-25.03%
logs_pretty_json	-20.63%	-10.77%	-1.22%	-30.04%
nexmark_json	-30.01%	-16.01%	-0.42%	-41.46%
nexmark_pretty_json	-21.35%	-15.76%	-1.09%	-34.47%
nexmark_bids_json	-26.64%	-22.20%	-3.01%	-44.64%
nexmark_bids_pretty_json	-26.26%	-22.16%	-2.64%	-44.12%
tweets_json	-20.36%	-18.97%	-14.85%	-45.05%
tweets_pretty_json	-22.61%	-15.10%	-11.04%	-41.55%
Average				-38.29%