Remove knapsack_merger since we don't use it anyway

spec/knapsack_merger.rb

-begin
-  class Knapsack::Report
-    alias_method :save_without_leading_existing_report, :save
-
-    def load_existing_report
-      Knapsack::Presenter.existing_report = open
-    rescue
-      false
-    end
-
-    def save
-      load_existing_report
-      save_without_leading_existing_report
-    end
-  end
-
-  class << Knapsack::Presenter
-    attr_accessor :existing_report
-
-    def initialize
-      @existing_report = []
-    end
-
-    def report_hash
-      return current_report_hash unless existing_report
-      existing_report.merge(current_report_hash).sort.to_h
-    end
-
-    def current_report_hash
-      Knapsack.tracker.test_files_with_time
-    end
-
-    def report_yml
-      report_hash.to_yaml
-    end
-
-    def report_json
-      JSON.pretty_generate(report_hash)
-    end
-  end
-end

spec/spec_helper.rb

@@ -16,7 +16,6 @@ require 'shoulda/matchers'
 require 'sidekiq/testing/inline'
 require 'rspec/retry'
 require 'knapsack'
-require_relative 'knapsack_merger'
 
 Knapsack::Adapters::RSpecAdapter.bind