[7.17] Fix NodeMetadataTests#testEqualsHashcodeSerialization (#83170) (#83194)

* Fix NodeMetadataTests#testEqualsHashcodeSerialization (#83170)

The mutation function would rarely fail to mutate the input object. This
commit fixes that.

Relates #82689

* Old-skool switch

Author: DaveCTurner

server/src/test/java/org/elasticsearch/env/NodeMetadataTests.java

@@ -52,19 +52,19 @@ public void testEqualsHashcodeSerialization() {
                         return new NodeMetadata(
                             randomAlphaOfLength(21 - nodeMetadata.nodeId().length()),
                             nodeMetadata.nodeVersion(),
-                            Version.CURRENT
+                            nodeMetadata.oldestIndexVersion()
                         );
                     case 1:
                         return new NodeMetadata(
                             nodeMetadata.nodeId(),
                             randomValueOtherThan(nodeMetadata.nodeVersion(), this::randomVersion),
-                            Version.CURRENT
+                            nodeMetadata.oldestIndexVersion()
                         );
                     default:
                         return new NodeMetadata(
                             nodeMetadata.nodeId(),
                             nodeMetadata.nodeVersion(),
-                            randomValueOtherThan(Version.CURRENT, this::randomVersion)
+                            randomValueOtherThan(nodeMetadata.oldestIndexVersion(), this::randomVersion)
                         );
                 }
             }