Do not normalize types in the api extraction phase

This is follow up on #737 with controversial bits removed.

In summary this PR:

  * drops type normalization in api phase but keeps dealiasing
  * fixes #736 and marks corresponding test as passing

I discussed type normalization with @adriaanm and according to him
sbt shouldn't call that method. The purpose of this method to
convert to a form that subtyping algorithm expects. Sbt doesn't need
to call it and it's fairly expensive in some cases.

Dropping type normalization also fixes #726 by not running into
stale cache in Scala compiler problem described in SI-7361.