Ensure that HACL* states are not read concurrently

[picnixz]

Bug report

Bug description:

Sometimes, it's possible to read an HACL* state concurrently:

• sha3 reads the live HACL state outside the object lock at six sites
• blake2's digest_size getter reads the live HACL state outside the lock

Instead, we can (1) add this static information just after construction (2) compute it inside the lock sections.

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-155835: fix digest_size and block_size data races on SHA-3 objects #155838
• gh-155835: fix digest_size data race on BLAKE-2 objects #155839