Defer cache format changes to 0.13 - #22128

We revert the cache-format stack so main retains the 0.12 cache formats and bucket versions. These changes are deferred to 0.13.

This reverts the following PRs together, including the six cache bucket bumps and the serialization and Windows lock-name changes that depend on them:

• Refresh HTTP cache policies in place #22052: Refresh HTTP cache policies in place
• Store source distribution revision IDs inline #22059: Store source distribution revision IDs inline
• Remove the legacy hash digest cache representation #22060: Remove the legacy hash digest cache representation
• Derive serialization for cached artifact records #22061: Derive serialization for cached artifact records
• Use bounded wheel cache lock names on Windows #22062: Use bounded wheel cache lock names on Windows
• Pack HTTP cache policy flags and optional integers #22078: Pack HTTP cache policy flags and optional integers
• Align cached HTTP policies within the payload buffer #22079: Align cached HTTP policies within the payload buffer