bug#22658: 25.1.50; `undo-auto--boundary-timer` -- is it necessary to put this on a the `timer-list'?

[Keith David Bershatsky]

I'm not sure when it came about, but there is a `undo-auto--boundary-timer` on 
a constant timer that didn't use to be there in previous versions of Emacs.  It 
affected my ability to work on some redisplay debugging, and there is no 
"convenient" way to just turn it off.

Inasmuch as Undo/Redo is such an important part of an editor, is there a way to 
bake this important feature into the C-source code so that it doesn't clutter 
up the timers and/or unnecessarily trigger a redisplay?

Thanks,

Keith

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In GNU Emacs 25.1.50.1 (x86_64-apple-darwin10.8.0, NS appkit-1038.36 Version 
10.6.8 (Build 10K549))
 of 2016-02-13 built on server.private
Repository revision: cebd899370fb3b143ba640c3b6499e982e869849
Windowing system distributor 'Apple', version 10.3.1038
Configured using:
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 CPPFLAGS=-I/Users/HOME/.0.data/.0.emacs/macports/include
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Recent messages:
Re-scanning...
Sorting by rdate...done
Constructing summary structure...done
Scoring...done
Emacs:  undo-auto--boundary-timer
Making change-major-mode-hook buffer-local while locally let-bound!
Saving...done
Undo...
Undo!
Loading msgdb for 
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