MYSQLDUMP_MAX_RECORDSIZE WITH PARALLEL>1

Problem:
--------
These tests innodb_pagesize_max_recordsize and mysqldump_max_recordsize
can be run only with --parallel=1 and all pb2 by default runs with
--parallel=8. So this essentially means that the tests are never run on pb2.

Fix:
----
1. Use --initialize to do proper bootstrap
2. Remove MTR hacks used at the end of tests
3. Use .inc files instead of duplicating code
4. Use small redo log size 5M for bootstrap