Revert "Work around ceylon/ceylon#6868"
Revert "Work around ceylon/ceylon#6868"

This reverts commit 75ac057fd6c1fdc8ef6dddb98a5dfb3d8384bb4c.

Doesn’t actually fix the prolems: with the module versions,
ceylon-compile-js refuses to compile. I found an alternative workaround
(see issue).

ceylon/ceylon.ast