Test with the new Typescript

[Urigo]

The next version (current master) of Typescript suppose to include the dynamic import syntax:

• Explore supporting ES import() proposal  microsoft/TypeScript#12364
• [Master] Remerge this back to master after fixing test failure  microsoft/TypeScript#16281
• [Master] wip-dynamic import microsoft/TypeScript#14774

Would it be possible to check if that will work using typescript@next ?