Fix alter table metadata lose data

Fix a bug in the `BasicDDLFunctions#alterTableRemoveOldStorage()` which, if the alter table didn't change the table and require moving the data for the table (i.e. a METADATA only change), would delete the data anyways. 

Update the AlterTableCAOIIT test to include data checks as well as schema structure checks. 
Oh, because it's a metadata change for the parent, but a group change for the child. got it.