Capture root logger output in e2e tests

This [would have helped us] find the reorg error much faster.

[would have helped us]: ethereum-optimism/optimism#11756

e2e/stack_test.go

@@ -68,6 +68,10 @@ func TestE2E(t *testing.T) {
 		require.NoError(t, env.Close())
 	}()
 
+	// Unfortunately, geth and parts of the OP Stack occasionally use the root logger.
+	// We capture the root logger's output in a separate file.
+	log.SetDefault(log.NewLogger(log.NewTerminalHandler(openLogFile(t, env, "root-logger"), false)))
+
 	if err := os.Mkdir(artifactsDirectoryName, 0o755); !errors.Is(err, os.ErrExist) {
 		require.NoError(t, err)
 	}