benchmark: drop all bm_ prefix for legacy driver.rb

benchmark/*.rb is only benchmarks now. We don't need prefixes.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63928 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

benchmark/vm_thread_sized_queue2.rb

@@ -0,0 +1,23 @@
+require 'thread'
+# one producer, many consumers
+n = 1_000_000
+m = 10
+q = Thread::SizedQueue.new(100)
+consumers = m.times.map do
+  Thread.new do
+    while q.pop
+      # consuming
+    end
+  end
+end
+
+producer = Thread.new do
+  while n > 0
+    q.push true
+    n -= 1
+  end
+  m.times { q.push nil }
+end
+
+producer.join
+consumers.each(&:join)