* ci: bump ci builder `0.50.0`

Bumps the `ci-builder` image with an updated version
of foundry.

Foundry update:
https://github.com/ethereum-optimism/optimism/pull/11325

Docker build:
https://app.circleci.com/pipelines/github/ethereum-optimism/optimism/60263/workflows/154fd94a-4029-4e2f-8bce-4ea4c6d25897

* contracts-bedrock: fix tests after new foundry version

* contracts-bedrock: comment why skip

* test: better comments

* gas-snapshot: regenerate

* snapshots: update

* snapshots: update

* fix(ctb): Align expected ptr in `Bytes.slice` test

An update to `forge-std` causes `bound` to set the free memory pointer
at an unaligned offset. This commit updates the test such that the
expected pointer is correctly aligned, without an assumption on the
starting ptr's alignment.

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Co-authored-by: clabby <ben@clab.by>