added fast_spec_helper in 2 more files

spec/rubocop/cop/avoid_return_from_blocks_spec.rb

 # frozen_string_literal: true
 
-require 'spec_helper'
+require 'fast_spec_helper'
 require 'rubocop'
-require 'rubocop/rspec/support'
 require_relative '../../../rubocop/cop/avoid_return_from_blocks'
 
-RSpec.describe RuboCop::Cop::AvoidReturnFromBlocks do
+RSpec.describe RuboCop::Cop::AvoidReturnFromBlocks, type: :rubocop do
   include CopHelper
 
   subject(:cop) { described_class.new }
@@ -29,7 +28,7 @@ RSpec.describe RuboCop::Cop::AvoidReturnFromBlocks do
         end
       end
     RUBY
-    expect_next_instance_of(described_class) do |instance|
+    expect_any_instance_of(described_class) do |instance|
       expect(instance).to receive(:add_offense).once
     end
 

spec/rubocop/cop/migration/drop_table_spec.rb

 # frozen_string_literal: true
 
-require 'spec_helper'
-
+require 'fast_spec_helper'
 require 'rubocop'
-require 'rubocop/rspec/support'
-
 require_relative '../../../../rubocop/cop/migration/drop_table'
 
-RSpec.describe RuboCop::Cop::Migration::DropTable do
+RSpec.describe RuboCop::Cop::Migration::DropTable, type: :rubocop do
   include CopHelper
 
   subject(:cop) { described_class.new }