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_symbol_block_pass.rb

@@ -0,0 +1,13 @@
+class C
+  1000.times {|i|
+    eval("def i#{i};end")
+  }
+end
+
+c = C.new
+m = C.instance_methods(false)
+5_000.times do
+  m.each do |n|
+    c.tap(&n)
+  end
+end