Merge #16911: wallet: Only check the hash of transactions loaded from disk

cd68594 Only check the hash of transactions loaded from disk (Andrew Chow)

Pull request description:

  It feels unnecessary to do a full `CheckTransaction` for every transaction saved in the wallet. It should not be possible for an invalid transaction to get into the wallet in the first place, and if there is any disk corruption, the hash check will catch it.

ACKs for top commit:
  MarcoFalke:
    ACK cd68594
  laanwj:
    ACK cd68594
  promag:
    ACK cd68594, AFAICT the check is not needed, hash comparison gives data integrity.

Tree-SHA512: 5b2e719f76097cfbf125392db6cc6c764355c81f0b7a5b60aee4b06af1afcca80cfd38a3cf5307fd9e2c1afc405f8321929a4552943099a8161e6762965451fb

Author: laanwj

src/wallet/walletdb.cpp

@@ -5,8 +5,6 @@
 
 #include <wallet/walletdb.h>
 
-#include <consensus/tx_check.h>
-#include <consensus/validation.h>
 #include <fs.h>
 #include <key_io.h>
 #include <protocol.h>
@@ -218,8 +216,7 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
             ssKey >> hash;
             CWalletTx wtx(nullptr /* pwallet */, MakeTransactionRef());
             ssValue >> wtx;
-            CValidationState state;
-            if (!(CheckTransaction(*wtx.tx, state) && (wtx.GetHash() == hash) && state.IsValid()))
+            if (wtx.GetHash() != hash)
                 return false;
 
             // Undo serialize changes in 31600