Update swap_column_names to execute ALTER TABLE directly

instead of using `rename_column` which has side effects (renames
_some_ indexes).

Releated to https://gitlab.com/gitlab-org/gitlab/-/issues/288005.

db/post_migrate/20210622041846_finalize_push_event_payloads_bigint_conversion.rb

@@ -40,7 +40,7 @@ class FinalizePushEventPayloadsBigintConversion < ActiveRecord::Migration[6.1]
 
       # Swap PK constraint
       execute "ALTER TABLE #{TABLE_NAME} DROP CONSTRAINT push_event_payloads_pkey"
-      rename_index TABLE_NAME, index_name(TABLE_NAME, column: :event_id), 'push_event_payloads_pkey'
+      rename_index TABLE_NAME, INDEX_NAME, 'push_event_payloads_pkey'
       execute "ALTER TABLE #{TABLE_NAME} ADD CONSTRAINT push_event_payloads_pkey PRIMARY KEY USING INDEX push_event_payloads_pkey"
 
       # Drop FK fk_36c74129da

lib/gitlab/database/migration_helpers.rb

@@ -1622,9 +1622,9 @@ into similar problems in the future (e.g. when new tables are created).
         end
 
         temp_name = "#{column_1}_tmp"
-        rename_column(table_name, column_1, temp_name)
-        rename_column(table_name, column_2, column_1)
-        rename_column(table_name, temp_name, column_2)
+        execute "ALTER TABLE #{quote_table_name(table_name)} RENAME COLUMN #{quote_column_name(column_1)} TO #{quote_column_name(temp_name)}"
+        execute "ALTER TABLE #{quote_table_name(table_name)} RENAME COLUMN #{quote_column_name(column_2)} TO #{quote_column_name(column_1)}"
+        execute "ALTER TABLE #{quote_table_name(table_name)} RENAME COLUMN #{quote_column_name(temp_name)} TO #{quote_column_name(column_2)}"
       end
 
       private

spec/lib/gitlab/database/migration_helpers_spec.rb

@@ -2995,6 +2995,8 @@ RSpec.describe Gitlab::Database::MigrationHelpers do
         t.integer :column_1
         t.bigint  :column_2
       end
+
+      model.add_index(table, :column_2)
     end
 
     after do
@@ -3011,6 +3013,13 @@ RSpec.describe Gitlab::Database::MigrationHelpers do
       expect(column_2.sql_type).to eq('integer')
     end
 
+    it 'does not rename indexes' do
+      model.swap_column_names(table, :column_1, :column_2)
+
+      index = model.indexes_for(table, :column_1).first
+      expect(index.name).to eq("index_#{table}_on_column_2")
+    end
+
     it 'raises an error when not in transaction' do
       expect(model).to receive(:transaction_open?).and_return(false)