Remove code for EE specific checks

This code is no longer needed in the single codebase setup.

lib/tasks/ee_compat_check.rake

-desc 'Checks if the branch would apply cleanly to EE'
-task ee_compat_check: :environment do
-  Rake::Task['gitlab:dev:ee_compat_check'].invoke
-end

lib/tasks/gitlab/dev.rake

-namespace :gitlab do
-  namespace :dev do
-    desc 'Checks if the branch would apply cleanly to EE'
-    task :ee_compat_check, [:branch] => :environment do |_, args|
-      opts =
-        if ENV['CI']
-          {
-            ce_project_url: ENV['CI_PROJECT_URL'],
-            branch: ENV['CI_COMMIT_REF_NAME'],
-            job_id: ENV['CI_JOB_ID']
-          }
-        else
-          unless args[:branch]
-            puts "Must specify a branch as an argument".color(:red)
-            exit 1
-          end
-
-          args
-        end
-
-      if File.basename(Rails.root) == 'gitlab'
-        puts "Skipping EE projects"
-        exit 0
-      elsif Gitlab::EeCompatCheck.new(opts || {}).check
-        exit 0
-      else
-        exit 1
-      end
-    end
-  end
-end

scripts/static-analysis

@@ -37,10 +37,6 @@ tasks = [
   %w[scripts/lint-rugged]
 ]
 
-if Gitlab.ee?
-  tasks.unshift(%w[ruby -rbundler/setup scripts/ee_specific_check/ee_specific_check.rb])
-end
-
 static_analysis = Gitlab::Popen::Runner.new
 
 static_analysis.run(tasks) do |cmd, &run|