Copying AUTO_INCREMENT value to ghost table

[shlomi-noach]

Initial commit: towards setting up a test suite

Solves github#381

Description

This PR ensures to copy AUTO_INCREMENT value to gh-ost table. The problem in github#381 is that if rows are deleted from end of table, then the new table is created (or ends up) with a lower auto_increment value. I think most migrations do not encounter this issue because new rows are commonly added to the table while it's being migrated, naturally bumping up the ghost table's AUTO_INCREMENT value to match the original table's. But for static tables this can happen.

• contributed code is using same conventions as original code
• script/cibuild returns with no formatting errors, build errors or unit test errors.

[shlomi-noach]

This PR now:

• parses user's -alter statement to see if the user has specified any explicit AUTO_INCREMENT
• reads original table's AUTO_INCREMENT value (if exists)
• if AUTO_INCREMENT exists, and user has not overriden, apply original table's AUTO_INCREMENT value onto the ghost table.
• tests added to verify behavior.