When selecting a package variant from an export map we should favor n… (#27030)

When selecting a package variant from an export map we should favor node
over edge-light

edge-light represents a runtime with some minimal set of web apis
generally found across edge runtimes. However some environments might be
both edge-light compatible and node compatible and (node is adding many
web APIs) and when both conditions exist we want to favor the node
implementations. A followup to this change will add the web streams APIs
to Flight and Fizz so the node version exports the same interfaces for
web streams that edge does in addition to the node specific
implementations.