Revert "SI-7517 type constructors too eagerly normalized."

This reverts commit 14534c693d2eb6acafaf8244c14b5643388fbd67.

It turns out this approach was breaking the working variations
in the submitted test case even as it was unbreaking the unworking
one, but I never managed to uncomment them. Fortunately retronym's
test case was not so lackadaisical.
Merge pull request #2624 from paulp/pr/revert-14534c693d

Revert "SI-7517 type constructors too eagerly normalized."