Remove Compression & Decompression from RLPMemo (#456)

* initial commit

* modify/add tests

* minor changes

* minor fixes

* add nibbleset in RlpMemo to remember the order

* nit spacing fix

* merge with latest main

* address comments, re-order header - breaking merkle computation tests

* improve test to catch failures

* minor whitespace fixes in test

* passing test + index at end

* improve dictionary/memo comparison

* add test case for keccak->rlp modification

* minor format changes in the new test

* fix issues

src/Paprika.Tests/Chain/PrefetchingTests.cs

@@ -71,67 +71,6 @@ public async Task Prefetches_properly_on_not_changed_structure()
         }
     }
 
-    [Test]
-    public async Task Makes_all_decompression_on_prefetch()
-    {
-        using var db = PagedDb.NativeMemoryDb(8 * 1024 * 1024, 2);
-        var merkle = new ComputeMerkleBehavior(ComputeMerkleBehavior.ParallelismNone);
-        await using var blockchain = new Blockchain(db, merkle);
-
-        // Create one block with some values, commit it and finalize
-        var hash = Keccak.EmptyTreeHash;
-
-        hash = BuildBlock(blockchain, hash, 1);
-        blockchain.Finalize(hash);
-        await blockchain.WaitTillFlush(hash);
-
-        hash = BuildBlock(blockchain, hash, 2);
-
-        return;
-
-        static Keccak BuildBlock(Blockchain blockchain, Keccak parent, uint number)
-        {
-            var isFirst = number == 1;
-
-            byte[] value = isFirst ? [17] : [23];
-
-            const int seed = 13;
-            const int contracts = 10;
-            const int slots = 10;
-
-            using var block = blockchain.StartNew(parent);
-            var random = new Random(seed);
-
-            // Open prefetcher on blocks beyond first
-            var prefetcher = isFirst == false ? block.OpenPrefetcher() : null;
-
-            for (var i = 0; i < contracts; i++)
-            {
-                var contract = random.NextKeccak();
-                prefetcher?.PrefetchAccount(contract);
-
-                if (isFirst)
-                {
-                    block.SetAccount(contract, new Account(1, 1, Keccak.Zero, Keccak.Zero));
-                }
-
-                for (var j = 0; j < slots; j++)
-                {
-                    var storage = random.NextKeccak();
-                    prefetcher?.PrefetchStorage(contract, storage);
-                    block.SetStorage(contract, storage, value);
-                }
-            }
-
-            prefetcher?.SpinTillPrefetchDone();
-
-            using (RlpMemo.NoDecompression())
-            {
-                return block.Commit(number);
-            }
-        }
-    }
-
     private static void Set(Keccak[] accounts, uint account, IWorldState start, UInt256 bigNonce)
     {
         ref var k = ref accounts[account];