refactor: move the halo2_common::arithmetic to halo2_backend(post fe-be split)

[duguorong009]

Description

• move the halo2_common::arithmetic::* to halo2_backend crate

Related issues

• [post frontend-backend split] Move types/functions from common to frontend/backend #266

Changes

• move the arithmetic.rs file to halo2_backend crate
• update the imports in related crates

Notes

The PR includes the following changes for CI check.

• bump up the rust-toolchain from 1.67.0 to 1.73.0
• add the resolver = "2" option in workspace cargo.toml file
• set the getrandom crate as dependency for wasm32-* build
• update module visibility, etc (fix clippy warnings)

[duguorong009]

@ed255
The CI complains the MSRV is incompatible with dependency crate(bumpalo).
The MSRV is v1.73.0 for bumpalo(v3.15.1), while v1.67.0 for halo2.
Do you think it is good to update the MSRV of halo2?

For additional info, the bumpalo crate is dependency of wasm-bindgen-backend crate.
As you can see in the following cargo.toml, the bumpalo version is v3.0.0.
https://github.com/rustwasm/wasm-bindgen/blob/main/crates/backend/Cargo.toml#L20
Hence, the cargo resolver automatically fetches the latest version of bumpalo. (currently, v3.15.1)
The MSRV of bumpalo has been updated to v1.73.0 in v3.15.0.

cc @CPerezz @davidnevadoc

[CPerezz]

@duguorong009 We're at 1.76 (see https://releases.rs/) version of stable.

It think 3 versions less for the MSRV update is fine.
This crate doesn't have an explicit MSRV policy, but if it did it would probably be similar to this proposed policy from libc: rust-lang/libs-team#72.

In general, I like the N-3 option.

[CPerezz]

LGTM.

[duguorong009]

@duguorong009 We're at 1.76 (see https://releases.rs/) version of stable.

It think 3 versions less for the MSRV update is fine. This crate doesn't have an explicit MSRV policy, but if it did it would probably be similar to this proposed policy from libc: rust-lang/libs-team#72.

In general, I like the N-3 option.

Thanks for quick reply!
Update the rustc version to v1.73.0 in rust-toolchain file. b535a18

[ed255]

LGTM! I noticed that this PR has many commits that are unrelated to the PR itself. For this reason I suggest using Squash and merge and cleaning up the commit message (basically removing the commit messages that are not applied here)

[ed255]

@duguorong009 note that the Stable lints CI check is not passing, you'll need to fix that before merging.

[CPerezz]

Once this is merged, will bump up the MSRV which will allow #282 to pass WASM compilation CI.

[duguorong009]

Once this is merged, will bump up the MSRV which will allow #282 to pass WASM compilation CI.

The CI still fails in wasm32-* build check with new errors.
Will try to debug why.

[CPerezz]

Ohh dammit I merged as I saw green light and the approvals! But the changes in 09aaf97 aren't OK.

I did it since it only should trigger for dev-dependencies.
Filled #285 for this.

This unblocks the merge of all other PRs.