Error comparing temperature units with offset

Hi,

In versiones newer than 11.4.1 the comparison of temperatures is incorrect between some temperature units when an offset is involved.

```jl
lowTemp = 9 degC;
highTemp = 10 degC;

lowTemp < highTemp # true
lowTemp to degF < highTemp # false but should be true
lowTemp to K < highTemp # false but should be true
lowTemp to degR < highTemp # false but should be true
lowTemp to K < highTemp to degF # false but should be true
lowTemp to degR < highTemp to degF # false but should be true
```

This was discussed in #2518 but this might need to be a separate issue.