US 22-056 9.12.3 [dcl.attr.assume] Remove or defuse "assume" attribute

[wg21bot]

This facility introduces more problems than it solves, especially from implementation perspective. In particular, it has ABI change implications that raises concerns from implementors and effective deployment. The existing implementation-defined extensions serve the purposes they are defined for (with their limitations).

Proposed change:

Either:

1. Entirely revert P1774, or Amend it to be completely ignorable as sequence of tokens, without forcing any odr-use of entities (which might trigger template instantiations and so forth)

[jfbastien]

Duplicate https://github.com/cplusplus/nbballot/issues/425

[erichkeane]

No objection to unanimous consent that this is a duplicate as stated above.