[lldb][tests][gmodules] Test for expression evaluator crash for types referencing the same template

The problem here is that the ASTImporter adds
the template class member FieldDecl to
the DeclContext twice. This happens because
we don't construct a `LookupPtr` for decls
that originate from modules and thus the
ASTImporter never realizes that the FieldDecl
has already been imported. These duplicate
decls then break the assumption of the LayoutBuilder
which expects only a single member decl to
exist.

The test will be fixed by a follow-up revision
and is thus skipped for now.

Differential Revision: https://reviews.llvm.org/D133944