chore: build query-engine-wasm with stable rust

[aqrln]

We previously used the nightly toolchain to build query-engine-wasm to make use of some nightly-only rustc and cargo flags in an attempt to reduce the size as much as possible, as our goal was to fit into the 1 MB gzip bundle limit in the Cloudflare Workers free plan, while still leaving enough space for the client and the user's application.

Specifically, we used it to:

• Rebuild the standard library with size optimizations and without the panic infrastructure, making all panics immediate aborts.
• Remove all panic location details. In the case of a crash, we (or the user) would only know that a problem happened but wouldn't know where and why (or possibly not even know it happened at all — see below).

Other the the last point above, which is obviously a problem, there are more:

• While abort in WASM immediately abort the Node.js process too, its behaviour on Cloudflare Workers is weird, and apparently somehow the JavaScript code may continue running and calling into QE again, leading to memory leaks and undefined behaviour.

• Keeping the nightly toolchain up to date is a hassle (as it's pinned) and we usually don't even bother doing it until it's too old. When we do, we either pick latest (which might have bugs) or need to spend time figuring out the last nightly for a specific version, which would correspond to it promoted to beta.

All in all, it is a maintenance burden, a source of technical debt, and the reason I can't consider query-engine-wasm production ready. Given that:

• we now have the query compiler project which reduces the size way further without these hacks
• removing these questionable size optimizations and switching to the stable toolchain increases the gzipped size by around 80 KB
• and Cloudflare has increased the limit on the free plan from 1 MB to 3 MB

I propose we accept this size increase and switch to the stable toolchain.

[codspeed-hq]

CodSpeed Performance Report

Merging #5167 will not alter performance

_{Comparing push-qkrsypxvlupy (180cfa8) with main (11f45a2)}

Summary

✅ 11 untouched benchmarks

[github-actions]

WASM Query Engine file Size

Engine	This PR	Base branch	Diff
Postgres	2.332MiB	2.111MiB	226.193KiB
Postgres (gzip)	929.568KiB	846.679KiB	82.889KiB
Mysql	2.291MiB	2.073MiB	223.063KiB
Mysql (gzip)	914.825KiB	832.296KiB	82.529KiB
Sqlite	2.197MiB	1.983MiB	219.390KiB
Sqlite (gzip)	876.532KiB	795.695KiB	80.837KiB

[FGoessler]

Sounds like fair tradeoffs to me - let's do this 👍

[aqrln]

@jkomyno pointed out that while it's not a concern anymore with Cloudflare Workers, it would still be a problem with Vercel Edge Functions on Hobby plan. What shall we do?