core: cleanup txlookup entries during chain rewind

[the-shadow-coder]

This PR addresses a todo on core/blockchain.go

		// Ignore the error here since light client won't hit this path
		frozen, _ := bc.db.Ancients()
		if num+1 <= frozen {
			// The chain segment, such as the block header, canonical hash,
			// body, and receipt, will be removed from the ancient store
			// in one go.
			//
			// The hash-to-number mapping in the key-value store will be
			// removed by the hc.SetHead function.
		} else {
			// Remove the associated body and receipts from the key-value store.
			// The header, hash-to-number mapping, and canonical hash will be
			// removed by the hc.SetHead function.
			rawdb.DeleteBody(db, hash, num)
			rawdb.DeleteReceipts(db, hash, num)
		}
		// Todo(rjl493456442) txlookup, log index, etc
	}
	

It addresses the todo by cleaning up txlookup entries during a chain rewind. When delFn deletes a block body, it now iterates through the transactions and removes their corresponding lookup indices, preventing stale "zombie" entries from persisting in the database. A regression test TestSetHeadTxLookupCleanup has been added to verify this behavior.