ActiveRecord::Tasks::DatabaseTasks.load_schema has always to establish database connection

When load schema from `structure.sql`, database connection isn't
  established. `ActiveRecord::Tasks::DatabaseTasks.load_schema` has to
  establish database connection since it executes
  ```
  ActiveRecord::InternalMetadata.create_table
  ActiveRecord::InternalMetadata[:environment] = environment
  ```

activerecord/lib/active_record/tasks/database_tasks.rb

@@ -228,13 +228,13 @@ module ActiveRecord
       def load_schema(configuration, format = ActiveRecord::Base.schema_format, file = nil, environment = env) # :nodoc:
         file ||= schema_file(format)
 
+        check_schema_file(file)
+        ActiveRecord::Base.establish_connection(configuration)
+
         case format
         when :ruby
-          check_schema_file(file)
-          ActiveRecord::Base.establish_connection(configuration)
           load(file)
         when :sql
-          check_schema_file(file)
           structure_load(configuration, file)
         else
           raise ArgumentError, "unknown format #{format.inspect}"

railties/test/application/rake/dbs_test.rb

@@ -189,6 +189,14 @@ module ApplicationTests
         db_structure_dump_and_load database_url_db_name
       end
 
+      test "db:structure:dump and db:structure:load set ar_internal_metadata" do
+        require "#{app_path}/config/environment"
+        db_structure_dump_and_load ActiveRecord::Base.configurations[Rails.env]["database"]
+
+        assert_equal "test", rails("runner", "-e", "test", "puts ActiveRecord::InternalMetadata[:environment]").strip
+        assert_equal "development", rails("runner", "puts ActiveRecord::InternalMetadata[:environment]").strip
+      end
+
       test "db:structure:dump does not dump schema information when no migrations are used" do
         # create table without migrations
         rails "runner", "ActiveRecord::Base.connection.create_table(:posts) {|t| t.string :title }"