Move DeriveContext(recursive) returned handle to NEW_CONTEXT_HANDLE

This aligns with the spec and is more consistent with all other
commands.

dpe/src/commands/derive_context.rs

@@ -242,10 +242,11 @@ impl CommandExecution for DeriveContextCmd {
  ..tmp_context
  };
 
- // No child context created so handle is unmeaningful
+ // Return new handle in new_context_handle
  Ok(Response::DeriveContext(DeriveContextResp {
- handle: ContextHandle::default(),
- parent_handle: dpe.contexts[parent_idx].handle,
+ handle: dpe.contexts[parent_idx].handle,
+ // Should be ignored since retain_parent cannot be true
+ parent_handle: ContextHandle::default(),
  resp_hdr: ResponseHdr::new(DpeErrorCode::NoError),
  }))
  } else {

verification/testing/deriveContext.go

@@ -435,7 +435,7 @@ func TestDeriveContextRecursiveOnDerivedContexts(d client.TestDPEInstance, c cli
  if err != nil {
  t.Fatalf("[FATAL]: Could not set TCI value: %v", err)
  }
- childHandle = &resp.ParentContextHandle
+ childHandle = &resp.NewContextHandle
 
  childHandle, childTcbInfo, err = getTcbInfoForHandle(c, childHandle)
  if err != nil {