tests, bench: Remove incorrect LoadWallet() calls

LoadWallet() must only be called immediately after a CWallet is
constructed, or not at all. Doing so after any other CWallet member
functions have been called may cause pointers and other objects
setup by other those functions to become invalidated.

Since these tests and benchmarks are using completely new wallets with
mock databases, it's not necessary to call LoadWallet() anyways, so
these can be dropped.

src/wallet/test/util.cpp

@@ -24,7 +24,6 @@ std::unique_ptr<CWallet> CreateSyncedWallet(interfaces::Chain& chain, CChain& cc
         LOCK2(wallet->cs_wallet, ::cs_main);
         wallet->SetLastBlockProcessed(cchain.Height(), cchain.Tip()->GetBlockHash());
     }
-    wallet->LoadWallet();
     {
         LOCK(wallet->cs_wallet);
         wallet->SetWalletFlag(WALLET_FLAG_DESCRIPTORS);