double db_drop_field in schema.test

Problem/Motivation

Unnecessary double call to db_drop_field on a test.

Proposed resolution

Remove it.

Remaining tasks

Reroll for D8.

User interface changes

None.

API changes

None.

Original report by aaaristo

  protected function assertFieldAdditionRemoval($field_spec) {
    global $oracle_debug;
    // Try creating the field on a new table.
    $table_name = 'test_table_' . ($this->counter++);
    $table_spec = array(
      'fields' => array(
        'serial_column' => array('type' => 'serial', 'unsigned' => TRUE, 'not null' => TRUE),
        'test_field' => $field_spec,
      ),
      'primary key' => array('serial_column'),
    );
    db_create_table($table_name, $table_spec);
    $this->pass(t('Table %table created.', array('%table' => $table_name)));

    // Check the characteristics of the field.
    $this->assertFieldCharacteristics($table_name, 'test_field', $field_spec);

    // Clean-up.
    db_drop_table($table_name);

    // Try adding a field to an existing table.
    $table_name = 'test_table_' . ($this->counter++);
    $table_spec = array(
      'fields' => array(
        'serial_column' => array('type' => 'serial', 'unsigned' => TRUE, 'not null' => TRUE),
      ),
      'primary key' => array('serial_column'),
    );
    db_create_table($table_name, $table_spec);
    $this->pass(t('Table %table created.', array('%table' => $table_name)));

    // Insert some rows to the table to test the handling of initial values.
    for ($i = 0; $i < 3; $i++) {
      db_insert($table_name)
        ->useDefaults(array('serial_column'))
        ->execute();
    }

    db_add_field($table_name, 'test_field', $field_spec);
    $this->pass(t('Column %column created.', array('%column' => 'test_field')));

    // Check the characteristics of the field.
    $this->assertFieldCharacteristics($table_name, 'test_field', $field_spec);

    // Clean-up.
    db_drop_field($table_name, 'test_field');  <------------------------------ this is already done by assertFieldCharacteristics!!
    db_drop_table($table_name);
  }

should we remove it?