Fix Array.from, entries, spread and other iterator related methods

[KurtGokhan]

Summary of fixes:

• Added Symbol.iterator to iterator objects
• Added String trimLeft and trimRight. They are the same as trimStart and trimEnd according to MDN
• Fixed Array.from, entries, spread syntax
  • Removed ExtractValueFromIteratorInstance method. It was causing trouble for nested arrays. I think it was added mistakenly because of the bug in entries
• Added Babel test which helped me catch all these errors

I was surprised that no tests fail because of entries change. Maybe there was no test coverage for that?

[lahma]

Great fixes, thank you! I tried with newer test262 test suite and some untested paths but none did show these problems so I guess the official test suite is just missing the coverage (or I can't find the correct place). Thanks for adding the missing coverage 👍🏻