DEV: spec hanging in CI (#22679)

Thread wakeup was failing to properly wake up thread under certain circumstances

Amend it so we use a tight loop instead.

spec/jobs/jobs_base_spec.rb

@@ -25,6 +25,14 @@ RSpec.describe ::Jobs::Base do
   class ConcurrentJob < ::Jobs::Base
     cluster_concurrency 1
 
+    def self.stop!
+      @stop = true
+    end
+
+    def self.stop
+      @stop
+    end
+
     def self.running?
       @running
     end
@@ -35,7 +43,7 @@ RSpec.describe ::Jobs::Base do
 
     def execute(args)
       self.class.running = true
-      sleep 20
+      sleep 0.0001 while !self.class.stop
     ensure
       self.class.running = false
     end
@@ -58,7 +66,8 @@ RSpec.describe ::Jobs::Base do
 
     expect(Sidekiq::Queues["default"][0]["args"][0]).to eq("test" => 100)
 
-    thread.wakeup
+    ConcurrentJob.stop!
+
     thread.join
   end