Based on Mozilla bugs 1270140, 1504656, 1483545, and 1504334.
Took note of Mozilla bug 1379222 which changed GetPrototypeFromCallableConstructor
to GetPrototypeFromBuiltinConstructor.
There are many other changes I did myself since the initial implementation by
Mozilla wouldn't work with this codebase.
- This adds the new Japanese ascension era (Reiwa)
- This updates timezone data to 2019a
- Updated script for git instead of SVN
- Regenerated locale data