Remove the _suppress_ctypes attribute from Block

[jsiirola]

Fixes # .

Summary/Motivation:

This PR removes the _suppress_ctypes attribute from Blocks. This was a hack put in 15 years ago to support PySP optimizations. It is not used anywhere in the codebase, or (to our knowledge) in any derived packages. Leaving it in was causing challenges when users were defining custom Block classes

Changes proposed in this PR:

• Remove the _suppress_ctypes attribute from all BlockData instances

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[mrmundt]

I looovveee the removal of unnecessary code.

[Robbybp]

Make it easier to subclass pyomo types!