another arguments object parsing

Before:
  benchmark
    simple call
      ✓ fn (602ms)
      ✓ overloadedFn (1921ms)
    overloaded call
      ✓ fn (607ms)
      ✓ overloadedFn (3450ms)


  4 passing (7s)

After: 
  benchmark
    simple call
      ✓ fn (607ms)
      ✓ overloadedFn (1323ms)
    overloaded call
      ✓ fn (576ms)
      ✓ overloadedFn (2779ms)


  4 passing (5s)