## Description 

Scope of this PR is:

- A function `update_lock_file_toolchain_version` to add compiler
version and build flags (AKA `BuildConfig`) to `Move.lock`
- Test for above
- Note the function is not "live" yet. It is not called when `sui move
build` is invoked.

Scope not in this PR (follow up to-be-done):

- Invoking `update_lock_file_toolchain_version` in the right place™️ 
- Adding lock file update logic (if toolchain version info exists, and
needs to be updated)
- Downloading / building with other versions of `sui`

**Review the first commit, the second is test output that needed to be
updated**

## Test Plan 

Added test

---
If your changes are not user-facing and not a breaking change, you can
skip the following section. Otherwise, please indicate what changed, and
then add to the Release Notes section as highlighted during the release
process.

### Type of Change (Check all that apply)

- [ ] protocol change
- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes