Context

On non-primaries, verify insert oplog entries: after applying the insert, re-read the document by RID, recompute its hash and size, and compare against the primary's m.h and m.sz.

On a mismatch, fassert with a stack crash until we have different modes for handling a mismatch.

Runs only on non-primaries (OplogApplication::Mode::kSecondary), with the feature flag on, for supported collections, and only when m.h is present. We may want to add a helper for checking these conditions.

Acceptance criteria

• After applying an insert on a non-primary, the document is fetched by RID; its hash (SHA-256) and size are computed and compared against m.h/m.sz.
• On mismatch, fassert and crash.
• Skipped on the primary, when the feature flag is off, on unsupported collections, and when m.h is absent.
• No update/delete handling. 
• Unit-test!