vcd2fsdb -compact: in our runs both smaller and faster than default; but it's a converter option, not a live-dump setting

When comparing waveform formats against FSDB, use its smallest setting, and know where that setting exists. The vcd2fsdb converter's -compact option (help: 'creates value changes in compact format, reduces file size and may take longer') was, in our runs on 9 open-source design dumps (W-2024.09), 1.6x to 11x smaller than the default, and also lower in CPU and wall on every design (about 30% higher MB per CPU-second over 4 quiet-host designs). Peak RSS was about the same (~90 MB). The help text's 'may take longer' didn't hold for us. Note that -compact belongs to the converter: a live simulator dump at default settings isn't compact, and the writer API's compression-method call is documented as obsolete. So a live-dump benchmark compares against FSDB's native dump, and a separate 'post-processed with vcd2fsdb -compact' row should include the conversion's own cost. Also: FSDB output isn't byte-deterministic (same input gives same size, different bytes), so compare sizes and decoded content, not hashes.