vlog95: trim binary constants to save space and emit size of undef. consts.
vlog95: trim binary constants to save space and emit size of undef. consts.

This should not change the functionality, but to save space trim any
unneeded bits from a binary constant. Also for the case of emitting
a signed undefined value when the allow signed flag is not set add
the width to the constant.

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