[v2] Reusing cache's better for performance usually but will make oracles not thread safe

[Vaibhavdixit02]

Describe the bug 🐞

The current state of affairs here reuses a bunch of caches needed in AD calls in oracles for allocation minimization, but this'll lead to the oracles being not thread-safe, what is a decent tradeoff, need to understand and update according to various parallelization possibilities (and GPU).