Migrations with --write-sql does not respect tables that are not created in database

[raph1mm]

Bug Report

Q	A
BC Break	no
Version	2.0.0

Summary

In case when there are two migrations, which first creates table and the second one - changes it - using --dry-run crashes migrations.

Current behavior

Migrations cannot "see" tables that are created only "virtually" during dry run. There is error:

There is no table with name 'my_db.my_table' in the schema.

How to reproduce

1. Create first migration with up() method:
   $schema->createTable('my_table');
2. Create second migration with up() method:
   $schema->getTable('my_table');
3. Run
   bin/console doctrine:migrations:migrate --write-sql='./my.sql'

Expected behavior

The expected behavior would be sql script with dumped all migrations - without any errors.