Fix issue 7147 typeid() should be supported in CTFE

Recognize the lowering which happens in the front-end, and change
it to a reference to the static 'typeinfo' variable.
Fix bad formatting in pull request 1897

It was incorrect in the case where offset is non-zero.
Merge pull request #1905 from donc/ctfe7417typeid

7147 typeid() should be supported in CTFE