chore(tdx): Split Out Mock Provider

### Description

#354 merged builder code from op-rbuilder into this repo.

In the tdx crate, a [MockProvider implementation](https://github.com/base/node-reth/blob/main/crates/builder/tdx-quote-provider/src/provider.rs) is shoehorned next to the prod provider. This ticket is to migrate this mock provider into test-utils

