[R4R] fix: remove diffhash patch introduced from separate node

[j75689]

Description

BSC has merged ethereum/go-ethereum#23628 to avoid hitting outdated snapshots, so we can remove #926 code that was introduced at the time to fix diffHash mismatch.

Rationale

In previous versions, the snapshot tree executed parent.flatten() without first locking the current difflayer when cap, but first executed the parent.flatten() to change it to be stale state and relinks the current difflayer.parent (removes the stale's difflayer from the recursive structure).

And this has caused a problem. There is a small chance that the stale difflayer will be obtained first when the difflayer is accessed externally, and then the difflayer.parent will be locked and re-linked, resulting in the snapshot being judged when acquiring the Account or Storage data. Returns null for Stale.

Therefore, in the implementation of #926, a new retry mechanism is added to retry when a null value is obtained, but this approach is not particularly good and may cause over-stack problems.

After the Ethereum version(ethereum/go-ethereum#23628) was merged, it was changed to lock the current difflayer first and then change the parent to avoid the above problems, so we can remove the patch fix introduced at that time.

Example

N/A

Changes

Notable changes:

• remove the patch from separate-node

[brilliant-lx]

LGTM.
It has been protected by diffLayer.lock right now.