Keep emit flags set on the original node on a namespace or enum node.
This prevents dropping flags like NoComments, which caused duplicated
comment emits.
Additionally, TypeScript would emit synthetic comments twice, once for
the variable declaration, once for the module statement. This explicitly
clears away synthetic comments on namespaces and enums if their
synthetic comments have already been emitted on the corresponding
variable statement.
Martin Probst
c50a6f7389