Remove spurious set name from eventsource.sharedworker.js (#15643)

Fix #15617

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

web_src/js/features/eventsource.sharedworker.js

@@ -1,5 +1,3 @@
-self.name = 'eventsource.sharedworker.js';
-
 const sourcesByUrl = {};
 const sourcesByPort = {};