Testing problems:

1.scc_feedback - Feedback is detected not in each case(with different
options).
2.splice/splice_port - No any changes in the dump after splice -port
command.
3.test_cell/test_cell_macc - ERROR: Assert `port_declared == true'
failed in kernel/rtlil.cc:1352.

This reverts commit c9a8d4a8.