Ruby

Implement Enumerator objects on VWA

This commit implements Enumerator objects on VWA. This speeds allocations
and decreases memory usage.

require "benchmark"

ary = []

puts(Benchmark.measure do
  10_000_000.times do
    u = ary.to_enum
  end
end)

puts `ps -o rss= -p #{$$}`

Before:

  1.500774   0.002717   1.503491 (  1.506791)
 18512

After:

  0.892580   0.002539   0.895119 (  0.897642)
 16480