Remove the unneeded Sized bound on TypeId creation

Remove the unneeded Sized bound on TypeId creation

This bound is probably unintentional and is unnecessarily
constricting.

To facilitate this change, it was also necessary to modify
resolve to recurse on and resolve type parameters in extern { }
blocks. This fixes an ICE when using bounds on type parameters
during the declaration of intrinsics.

This also adds tests for TypeId on both Sized and Unsized
tests as well as a test for using type parameters and bounds
in extern { } blocks.