Move vtorc from go-sqlite3 to modernc.org/sqlite

[dbussink]

This moves vtorc from the go-sqlite3 library that uses CGO, to use modernc.org/sqlite which is a pure Go implementation.

vtorc is the only component we have to build with CGO but it's causing pain for releases since we need to build it against an old Linux for linking against glibc.

Using modernc.org/sqlite allows for using Go only again and makes all Vitess components buildable without CGO.

In
https://datastation.multiprocess.io/blog/2022-05-12-sqlite-in-go-with-and-without-cgo.html someone ran some basic benchmarks. It shows that the pure Go version can be twice as slow, but the usage of vtorc is very limited and we operate on small datasets, so I think the performance impact purely of a somewhat slower sqlite implementation is negligable.

None of this is in a hot query serving path or anything like that, so I have little concern performance wise.

Related Issue(s)

• Fixes: Releases: VTOrc Unusable on Many Linux Platforms #12185
  • This provides a fundamental fix by removing the entire problem so we don't have to worry about how we build vtorc since we don't need CGO.

Checklist

• "Backport to:" labels have been added if this change should be back-ported
• Tests were added or are not required
• Documentation was added or is not required

[vitess-bot]

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[GuptaManan100]

LGTM!

[mattlord]

NICE! Thank you! ❤️

[vitess-bot]

I was unable to backport this Pull Request to the following branches: release-15.0.

[dbussink]

Manual backport in #12223