Add context information to `not a constructor` `TypeError`

[raskad]

There are a few places where we throw a TypeError signaling that a value is not a constructor. Right now those errors do not contain specific information to find out why or where the error occurred.

• The produced error should contain useful information (variable name(?), type of the value (?)) that makes it easier to find out why the error occurred.
• All of the places where we throw this error should have a similar syntax for the error text.

[Razican]

This also happens where we have "not a callable function".