Blob.text and Blob.arraybuffer are 10x+ slower on 20.x

The blob/blob.js benchmark is taking hours: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/1402/console

This probably didn't take so long in the past, there is this PR that changed the Blob's behavior a lot: https://github.com/nodejs/node/pull/45258/

From what I saw, the problem is in the JS->C++ transitions, for each piece of data it crosses JS->C++.

Furthermore, the text function expects arraybuffer and then calls decode, when we could just decode the data as soon as we get it from the C++ instead of keeping everything in memory and then discarding it.

I can do some optimizations on the JS side but I think this could be largely improved if we do the heavy operations on C++, I have no idea how to handle the asynchronous code on C++, so I accept some hints or if anyone wants to try work on this.

Start with the blob/blob.js benchmark and compare its current behavior with the Blob changes in PR #45258. Trace the JS-to-C++ transitions used by text and arraybuffer, then rerun the benchmark; done means the benchmark no longer takes hours and the Blob operations show a substantial performance improvement.