Correct licensing (#1608)

In order to satisfy the project's formatting rules, license information
was inserted into a number of files where it had been mistakenly omitted
by the original contributors [1]. In many cases, the license information
did not accurately describe the contributor or the time of contribution.
Update the information according to the information provided by the
contributors at the time each file was authored:

- atomicsHelper.js - a72ee6d9
- detachArrayBuffer.js - 70c7375b
- nans.js - b17ffc02
- nativeFunctionMatcher.js - 6b7cbb50
- proxyTrapsHelper.js d530c87b
- regexpUtils.js - 44b40e08
- tcoHelper.js - 4dc81d37

[1] 4ea2931f