static Lifespan nowOnMaybeScratch(long snap) {
		if (isScratch(snap)) {
			return new Impl(snap, -1);
		}
		return new Impl(snap, Long.MAX_VALUE);
	}
Get the lifespan from the given snap into the indefinite future, considering scratch space

<p>
If the snapshot is in scratch space, then the span will have an upper endpoint of -1, the
last scratch snapshot. Otherwise, this is the same as {@link #nowOn(long)}.

@param snap
@return the lifespan
Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/model/Lifespan.java