Iogi tests refactoring to make code clean

Closes #817 

With this pull request I did a small refactor to improved code readability, reducing complexity to allow us to keep maintainability too easy.

`ParametersProviderTest` was merged with `IogiParametersProviderTest`. In the past, when we had OGNL and Iogi living togheter, this class was useful. But from now this class is unnecessary, and keep the code hard to understand, because some code are splited in two places.

Some code are unnecessary after new `ParameterValue` was improved. So a lot of lines are dropped. Some pieces of code are changed to reduce complexity like extracting repeated code to methods, instantiating objects only when need, and a bit more.