Remove extra bounds checks from memo table hot-paths

[ibraheemdev]

This is just a small optimization that takes advantage of the fact that an index being valid for a MemoTable guarantees that it is valid for the corresponding MemoTableTypes, so we can avoid the duplicate bounds checks here.

It would be nice if we could remove the bounds and type checks here completely, but I don't think that's possible because we sometimes compute the MemoIngredientIndex from a salsa supertype Id, which could be smuggled across databases.

[netlify]

✅ Deploy Preview for salsa-rs canceled.

Name	Link
🔨 Latest commit	be3c4db
🔍 Latest deploy log	https://app.netlify.com/projects/salsa-rs/deploys/687c2e24b4b8260008e20bea

[codspeed-hq]

CodSpeed Performance Report

Merging #938 will not alter performance

_{Comparing ibraheemdev:ibraheem/unchecked-memo-table (be3c4db) with master (dba66f1)}

Summary

✅ 12 untouched benchmarks