Don't profile creating the env object

Author: ahx

benchmarks/profile.rb

@@ -10,7 +10,6 @@
 
 Vernier.trace(out: 'profiles/request_validation_profile.json') do
   1000.times do
-    env = Rack::MockRequest.env_for('/hello?filter[id]=1,2')
     definition.validate_request(Rack::Request.new(env), raise_error: true)
   end
 end