rebase, and document BonsaiReferenceTestWorldState bypass of stateroo…

…t check.

Signed-off-by: garyschulte <[email protected]>

ethereum/referencetests/src/main/java/org/hyperledger/besu/ethereum/referencetests/BonsaiReferenceTestWorldState.java

@@ -75,9 +75,18 @@ public ReferenceTestWorldState copy() {
         layerCopy, cachedMerkleTrieLoader, trieLogManager, preImageProxy);
   }
 
+  /**
+   * If the supplied header has a non-zero state root, verify. Else we assume that stateroot is an
+   * output instead of an input for this reference test and we bypass the state root check.
+   *
+   * <p>Besu reference-test style test cases should supply a stateroot to verify to prevent bonsai
+   * regressions.
+   *
+   * @param calculatedStateRoot state root calculated during bonsai persist step.
+   * @param header supplied reference test block header.
+   */
   @Override
   protected void verifyWorldStateRoot(final Hash calculatedStateRoot, final BlockHeader header) {
-    // if the supplied header has a non-zero state root, verify.  Else bypass
     if (!header.getStateRoot().equals(Hash.ZERO)) {
       super.verifyWorldStateRoot(calculatedStateRoot, header);
     }