ref(grouping): Small changes to grouping tests

[lobsterkatie]

This includes two small changes pulled out of an upcoming PR to make it easier to review:

• Add some grouping inputs to illustrate the upcoming fix. Also rename a related input to better distinguish it from the new ones.

• Add an assertion (currently failing for the new inputs) to show that we're not relying on chained exception error handling when filtering exception groups.

[codecov]

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All modified and coverable lines are covered by tests ✅

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Additional details and impacted files

@@           Coverage Diff           @@
##           master   #93960   +/-   ##
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  Coverage   88.03%   88.03%           
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  Files       10350    10350           
  Lines      598214   598222    +8     
  Branches    23227    23227           
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+ Hits       526651   526674   +23     
+ Misses      71058    71043   -15     
  Partials      505      505