Use regenerator-transform to implement babel-plugin-transform-regener…

…ator (babel#4881)

* Use regenerator-transform to implement babel-plugin-transform-regenerator.

Though I believe this is safe to merge, you may want to wait to merge it
until facebook/regenerator#259 is merged. That
pull request also provides more explanation of why I think moving the
implementation of Regenerator back to its original repository is a good
idea. I'm happy to compromise on anything necessary to make this happen.

Note that the regenerator-transform version is pegged to an exact version
(0.9.7). Past experience has taught me that releasing new versions of
Regenerator is almost impossible if client projects are allowed to pull in
new patch versions automatically. I will happily submit a pull request
whenever a new version is released.

* Remove never-used babel-plugin-transform-regenerator/.test directory.

* regenerator-transform to 0.9.8

packages/babel-plugin-transform-regenerator/package.json

@@ -7,9 +7,7 @@
   "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-regenerator",
   "main": "lib/index.js",
   "dependencies": {
-    "babel-types": "^6.16.0",
-    "babel-runtime": "^6.9.0",
-    "private": "~0.1.5"
+    "regenerator-transform": "0.9.8"
   },
   "license": "BSD",
   "devDependencies": {