Revert "Work around ceylon/ceylon-compiler#1665"

This reverts commit 264efed334e202064902bf1a61f5617833b56b44.

The workaround didn’t actually work, was ugly as hell, and @FroMage
fixed the bug (thanks!), so good riddance :)
Merge branch 'compilerBugStillThere'

Conflicts:
	source/ceylon/ast/api/TypeNameWithArguments.ceylon

ceylon/ceylon-compiler#1672 was fixed, it seems.