Cleanup unneeded vectors in a delay after initialization.
Cleanup unneeded vectors in a delay after initialization.

For a delay we do not know exactly what type we will be propagating
until the initialization event has happened. Because of this we
allocate both a vec4 and a vec8 value. Once the initialization event
has happened we can free the unneeded element(s).

CastMi/iverilog,themperek/iverilog,CastMi/iverilog,themperek/iverilog,themperek/iverilog,CastMi/iverilog