Normalize db/table name in the alter table operation in HMS

Normalize db/table names in alter table event in the HMS.

In create_table_core(), we do the following

tbl.setDbName(normalizeIdentifier(tbl.getDbName()));
tbl.setTableName(normalizeIdentifier(tbl.getTableName())); 

But in the alter_table, we are just taking case insensititive names and firing the alter_table event

firePreEvent(new PreAlterTableEvent(oldt, newTable, this)); 

As a result, event consumers of HMS like Impala would face issues with the case insensitive names while consuming events.