Merge bitcoin/bitcoin#27810: fuzz: Partially revert #27780

71200ac [fuzz] Only check duplicate coinbase script when block was valid (dergoegge)

Pull request description:

  Partially revert #27780, because moving the duplicate coinbase check out of the `was_valid` branch leads to non-bug crashes in the fuzz target.

  For context and further explanation see: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=59516

ACKs for top commit:
  MarcoFalke:
    nice lgtm ACK 71200ac

Tree-SHA512: 8c38e5ff9de6331016b9a0c5e435d007d46186151b04c09085f617bb31627a28ad56678066fe152372a3ad8656f026439e3e2f9ee61d7ef588072aef8124eaa3

Author: fanquake

src/test/fuzz/utxo_total_supply.cpp

@@ -144,13 +144,13 @@ FUZZ_TARGET(utxo_total_supply)
                 node::RegenerateCommitments(*current_block, chainman);
                 const bool was_valid = !MineBlock(node, current_block).IsNull();
 
-                if (duplicate_coinbase_height == ActiveHeight()) {
-                    // we mined the duplicate coinbase
-                    assert(current_block->vtx.at(0)->vin.at(0).scriptSig == duplicate_coinbase_script);
-                }
-
                 const auto prev_utxo_stats = utxo_stats;
                 if (was_valid) {
+                    if (duplicate_coinbase_height == ActiveHeight()) {
+                        // we mined the duplicate coinbase
+                        assert(current_block->vtx.at(0)->vin.at(0).scriptSig == duplicate_coinbase_script);
+                    }
+
                     circulation += GetBlockSubsidy(ActiveHeight(), Params().GetConsensus());
                 }