ENT-6357: Deserialize LedgerTransaction elements for each Contract.verify(). (#6962)

* ENT-6357: Deserialize LedgerTransaction elements for each Contract.verify().

* Lock the LedgerTransaction and NetworkParameters objects down for contract verification.

* Refactor BasicVerifier to be package private instead of public.

* Simplify verifyConstraints() operation.

* Review fixes: replace HashSet with LinkedHashSet, and add signing parties to commands via mapIndexed.

* Ensure tests also run notary nodes "out of process".

* Streamline SerializationContext switching.

* Cache deserialised cryptographic instances during contract verification.

* Invoke Class.forName() instead of ClassLoader.loadClass() to reduce contention on the system classloader's lock.

* Deserialization cache key now pre-computes its hash code.

* Allow AttachmentsClassLoader to be used concurrently.

* Cache all Envelope objects for reuse during contract verification.

* Generate CertPathProxy hash code using conventional algorithm.

* Adjust CustomSerializer.Proxy to allow better access to SerializationContext.

node-api/src/main/kotlin/net/corda/nodeapi/internal/serialization/kryo/KryoCheckpointSerializer.kt

@@ -90,7 +90,7 @@ object KryoCheckpointSerializer : CheckpointSerializer {
      */
     private fun getInputClassForCustomSerializer(classLoader: ClassLoader, customSerializer: CustomSerializerCheckpointAdaptor<*, *>): Class<*> {
         val typeNameWithoutGenerics = customSerializer.cordappType.typeName.substringBefore('<')
-        return classLoader.loadClass(typeNameWithoutGenerics)
+        return Class.forName(typeNameWithoutGenerics, false, classLoader)
     }
 
     /**