Add request tags just after span creation

For web spans, add request tags just after span creation instead of when
span finishes. This is needed for profiler code hotspots implementation
to determine which span are web spans and should be used to find current
endpoint.

Author: nsavoire

packages/dd-trace/src/plugins/util/web.js

@@ -103,6 +103,7 @@ const web = {
     context.res = res
 
     this.setConfig(req, config)
+    addRequestTags(context)
 
     return span
   },