cmd/devp2p/internal/ethtest: remove TD from status validation (#31137)

After recent changes in Geth (removing TD):

39638c8#diff-d70a44d4b7a0e84fe9dcca25d368f626ae6c9bc0b8fe9690074ba92d298bcc0d

Non-Geth clients are failing many devp2p tests with an error:
`peering failed: status exchange failed: wrong TD in status: have 1 want 0`

Right now only Geth is passing it - all other clients are affected by
this change. I think there should be no validation of TD when checking `Status`
message in hive tests. Now Geth has 0 (and hive tests requires 0) and
all other clients have actual TD. And on real networks there is no validation
of TD when peering

cmd/devp2p/internal/ethtest/conn.go

@@ -316,9 +316,6 @@ loop:
 				return fmt.Errorf("wrong head block in status, want:  %#x (block %d) have %#x",
 					want, chain.blocks[chain.Len()-1].NumberU64(), have)
 			}
-			if have, want := msg.TD.Cmp(chain.TD()), 0; have != want {
-				return fmt.Errorf("wrong TD in status: have %v want %v", have, want)
-			}
 			if have, want := msg.ForkID, chain.ForkID(); !reflect.DeepEqual(have, want) {
 				return fmt.Errorf("wrong fork ID in status: have %v, want %v", have, want)
 			}