simplify tests Expr.is_zero before _eval_simplify

[smichr]

References to other Issues or PRs

fixes #7971 by adding a test for is_zero in the simplification routine
closes #17088

This only returns 0 for an object that is zero which,
when multiplied by zero, gives 0 (not an object like
Matrix.zeros(2).

Release Notes

• simplify
  • simplify tests for Expr.is_zero

[sympy-bot]

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• simplify
  • simplify tests for Expr.is_zero (#17110 by @smichr)

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#### References to other Issues or PRs
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fixes #7971 by adding a test for `is_zero` in the simplification routine
closes #17088

This only returns 0 for an object that is zero which,
when multiplied by zero, gives 0 (not an object like
Matrix.zeros(2).

#### Release Notes

<!-- Write the release notes for this release below. See
https://github.com/sympy/sympy/wiki/Writing-Release-Notes for more information
on how to write release notes. The bot will check your release notes
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<!-- BEGIN RELEASE NOTES -->
- simplify
    - simplify tests for Expr.is_zero
<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

[codecov]

Codecov Report

Merging #17110 into master will decrease coverage by 0.013%.
The diff coverage is 100%.

@@              Coverage Diff              @@
##            master    #17110       +/-   ##
=============================================
- Coverage   74.498%   74.484%   -0.014%     
=============================================
  Files          623       623               
  Lines       161217    161219        +2     
  Branches     37846     37847        +1     
=============================================
- Hits        120104    120083       -21     
- Misses       35787     35810       +23     
  Partials      5326      5326