Add UMD testing bundles

[pkozlowski-opensource]

We need to add testing UMD bundles. Testing bundles should mirror UMD bundles we publish today, so we would have testing bundles for "core" (angular2-testing.umd.js) and all (angular2_all-testing.umd.js).

Both bundles should have source maps. We don't need minified version. Corresponds to dev.

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