Release 12.1.1

This release contains a variety of fixes from 12.1-1. For information about new features in major release 12, see Release 12.1.0.

A dump/restore is not required for those running 12.1.X.

• Support ALTER UNDO command.
• Remove the storage parameter initialpages of undo segment.
• Chinese text search parser can identify and filter stop words.
• Fix possible crash when PL/Scheme converts SQL null values and Scheme null values.
• The name of the wait event of the SpinLock type is changed to the camel-backed name.