set comprehension optimizer + tests

src/main/java/de/tlc4b/analysis/Typechecker.java

...4b/analysis/transformation/SetComprehensionOptimizer.java

...ava/de/tlc4b/analysis/typerestriction/TypeRestrictor.java

src/main/java/de/tlc4b/util/UtilMethods.java

...java/de/tlc4b/analysis/SetComprehensionOptimizerTest.java

src/test/java/de/tlc4b/util/TestUtil.java

src/test/java/testing/Testing.java