When retrying in ruby's test, it seems possible that `Gem` is not
loaded.

```
  1) Error:
TC_Set_Builtin#test_to_set:
NameError: uninitialized constant TC_Set_Builtin::Gem
    /export/home/chkbuild/chkbuild-gcc/tmp/build/20220708T070011Z/ruby/test/test_set.rb:844:in `should_omit?'
    /export/home/chkbuild/chkbuild-gcc/tmp/build/20220708T070011Z/ruby/test/test_set.rb:869:in `test_to_set'

  2) Error:
TC_Set_Builtin#test_Set:
NameError: uninitialized constant TC_Set_Builtin::Gem
    /export/home/chkbuild/chkbuild-gcc/tmp/build/20220708T070011Z/ruby/test/test_set.rb:844:in `should_omit?'
    /export/home/chkbuild/chkbuild-gcc/tmp/build/20220708T070011Z/ruby/test/test_set.rb:849:in
    `test_Set'
```

This is by `Gem::Version` only, just compare as array of integers
instead.