node v4 fails to reassignes const in for-of loops properly - #4309

What kind of change does this PR introduce?

bugfix

Did you add tests for your changes?

N/A

If relevant, link to documentation update:

N/A

Summary

In node v4 a for(const foo of bar) loop is not correctly evaluated:

Actual:

> for(const x of [1,2,3]) {console.log(x)}
1
1
1
undefined

expected:

> for(let x of [1,2,3]) {console.log(x)}
1
2
3

Does this PR introduce a breaking change?

No