Group similar failures together even though the description is slightly different

[spadapet]

Also, allow the grouped row to be expanded to show each individual failure.

Old:

• Count=1, Description=Value 22 cannot be set on property blah blah...
• Count=1, Description=Value 30 cannot be set on property blah blah...
• Count=1, Description=Value 38 cannot be set on property blah blah...
• Count=1, Description=Value 42 cannot be set on property blah blah...

New:

• Count=4, Description=Value 22 cannot be set on property blah blah...
  • Value 22 cannot be set on property blah blah...
  • Value 30 cannot be set on property blah blah...
  • Value 38 cannot be set on property blah blah...
  • Value 42 cannot be set on property blah blah...

The new version starts off collapsed