Added ".." and "..." infix operators. Num implements them to
return Range objects. Those in turn implement the iterator
protocol, so now numeric for loops are easy:
for (i in 1..10) { ... }
I also cleaned up the Wren benchmarks to use this.
In the process, I discovered the method_call benchmark really
just showed loop peformance, so I unrolled the loops in all of
the languages to stress method calls.
This also fixes a bug where constructors weren't being bound
correctly, and eliminates some unneeded instructions when
compiling ifs.
I also tweaked the other method_call languages to match Wren's.
Since Wren needs to do a super call to get to the parent _count,
the other languages do now too.
This is nice too because it means we're benchmarking super
calls.
