More tweaking of vga heuristics.
 [rsc] --rw-rw-r-- M 491481 glenda sys 13831 Nov 30 08:13 sys/src/9/pc/screen.c
	/n/sourcesdump/2005/1130/plan9/sys/src/9/pc/screen.c:469,475 - 
	/n/sourcesdump/2005/1201/plan9/sys/src/9/pc/screen.c:469,477
	  			continue;
	  		if(best==-1 
	  		|| p->mem[i].size > p->mem[best].size 
	- 		|| (p->mem[i].size == p->mem[best].size && (p->mem[i].bar&8)))
	+ 		|| (p->mem[i].size == p->mem[best].size 
	+ 		  && (p->mem[i].bar&8)
	+ 		  && !(p->mem[best].bar&8)))
	  			best = i;
	  	}
	  	if(best >= 0){