feat: Add CollectionIsEmptyProcessor (SonarSource rule 1155)

[fermadeiral]

This PR adds a processor for the rule Collection.isEmpty() should be used to test for emptiness.

Example repair:

- if (myCollection.size() == 0) {  // Noncompliant
+ if (myCollection.isEmpty()) {
...  
- if (myCollection.size() != 0) {  // Noncompliant
+ if (!myCollection.isEmpty()) {

[fermadeiral]

The method not(CtExpression<T> expr) is a copy from another processor. We should have something like SpoonUtils to keep these utility methods together and accessible to all processors. I believe this should be handled in a different PR though.

[slarse]

A raw type cast, otherwise LGTM!

The method not(CtExpression<T> expr) is a copy from another processor. We should have something like SpoonUtils to keep these utility methods together and accessible to all processors. I believe this should be handled in a different PR though.

Agree, we should have a utility class with static methods for this kind of thing.