Add EachWithIndexIterableTest & EachWithIndexIteratorTest
Add EachWithObjectIterableTest & EachWithObjectIteratorTest
Add PermutationIterableTest & PermutationIteratorTest
Add ProductIterableTest & ProductIteratorTest
Make RubyArray#push accept varargs
Check isVarArgs while injecting
Add RangeIterableTest & RangeIteratorTest
Add RepeatedCombinationIterableTest & RepeatedCombinationIteratorTest