Debug Info: instead of calling addToContextOwner which constructs the context

Debug Info: instead of calling addToContextOwner which constructs the context
after the DIE creation, we construct the context first.

Ensure that we create the context before we create a type so that we can add
the newly created type to the parent. Remove last use of addToContextOwner
now that it's not needed.

We use createAndAddDIE to wrap around "new DIE(". Now all shareable DIEs
should be added to their parents right after the creation.

Reviewed off-list by Eric, Thanks.

llvm-svn: 193657