reestablish previous connection after creating all databases

creating all databases mutates the connection pool.  This patch restores
the connection pool to the connection spec established before creating
all databases.  Fixes #23279

Author: tenderlove

activerecord/lib/active_record/tasks/database_tasks.rb

@@ -116,7 +116,11 @@ def create(*arguments)
       end
 
       def create_all
+        old_pool = ActiveRecord::Base.connection_handler.retrieve_connection_pool(ActiveRecord::Base)
         each_local_configuration { |configuration| create configuration }
+        if old_pool
+          ActiveRecord::Base.connection_handler.establish_connection(ActiveRecord::Base, old_pool.spec)
+        end
       end
 
       def create_current(environment = env)

railties/test/application/test_runner_test.rb

@@ -502,6 +502,19 @@ def test_pass_TEST_env_on_rake_test
       assert_match '1 runs, 1 assertions', output
     end
 
+    def test_rails_db_create_all_restores_db_connection
+      create_test_file :models, 'account'
+      output =  Dir.chdir(app_path) { `bin/rails db:create:all db:migrate && echo ".tables" | rails dbconsole` }
+      assert_match "ar_internal_metadata", output, "tables should be dumped"
+    end
+
+    def test_rails_db_create_all_restores_db_connection_after_drop
+      create_test_file :models, 'account'
+      Dir.chdir(app_path) { `bin/rails db:create:all` } # create all to avoid warnings
+      output =  Dir.chdir(app_path) { `bin/rails db:drop:all db:create:all db:migrate && echo ".tables" | rails dbconsole` }
+      assert_match "ar_internal_metadata", output, "tables should be dumped"
+    end
+
     def test_rake_passes_TESTOPTS_to_minitest
       create_test_file :models, 'account'
       output =  Dir.chdir(app_path) { `bin/rake test TESTOPTS=-v` }