Use thread support helper in concurrent insert tag spec (#37112)

spec/models/tag_spec.rb

@@ -287,16 +287,10 @@ RSpec.describe Tag do
       tag_name_upper = 'Rails'
       tag_name_lower = 'rails'
 
-      threads = []
-
-      2.times do |i|
-        threads << Thread.new do
-          described_class.find_or_create_by_names(i.zero? ? tag_name_upper : tag_name_lower)
-        end
+      multi_threaded_execution(2) do |index|
+        described_class.find_or_create_by_names(index.zero? ? tag_name_upper : tag_name_lower)
       end
 
-      threads.each(&:join)
-
       tags = described_class.where('lower(name) = ?', tag_name_lower.downcase)
       expect(tags.count).to eq(1)
       expect(tags.first.name.downcase).to eq(tag_name_lower.downcase)

spec/support/threading_helpers.rb

@@ -6,10 +6,10 @@ module ThreadingHelpers
   def multi_threaded_execution(thread_count)
     barrier = Concurrent::CyclicBarrier.new(thread_count)
 
-    threads = Array.new(thread_count) do
+    threads = Array.new(thread_count) do |index|
       Thread.new do
         barrier.wait
-        yield
+        yield(index)
       end
     end