don't run memspecs as part of CI build.

Rakefile

@@ -15,7 +15,9 @@ Rake::ExtensionTask.new("init", eval(File.read("therubyracer.gemspec"))) do |ext
 end
 
 require 'rspec/core/rake_task'
-RSpec::Core::RakeTask.new(:spec)
+RSpec::Core::RakeTask.new(:spec) do |task|
+  task.rspec_opts = '--tag ~memory'
+end
 
 task :sanity => [:clean, :compile] do
   sh %q{ruby -Ilib -e "require 'v8'"}

spec/mem/blunt_spec.rb

@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-describe "A Very blunt test to make sure that we aren't doing stupid leaks" do
+describe "A Very blunt test to make sure that we aren't doing stupid leaks", :memory => true do
   before do
     if Object.const_defined?(:RUBY_ENGINE) && RUBY_ENGINE == 'rbx'
       pending 'need to figure out how to do memory sanity checks on rbx'