* Verify parsers against same snapshot
- Reworked run_spec, now accepts 3th optional array argument for
additional parsers to verify against
- Merged duplicate run_spec configs
- Removed duplicate snapshot data
* Formatted run_spec.js with prettier
* Fixed node4 incompatibility
The previous API was inconsistent. The new one is
```js
--parser flow
--parser babylon
{parser: 'flow'}
{parser: 'babylon'}
```
if we ever want to add new parsers in the future it'll allow that more easily.
I put a console.log in parser.js in both functions and tested that the test suite worked both with and without the change in run_spec. I also tested that both the previous and new command line options are working.
At some point in the future we'll likely want to get rid of the old api but might as well keep supporting it so we don't break anyone for now.
Wei-Wei Wu