Update JavaParser version and fix configured smells being ignored

[marvinkreis]

This updates the JavaParser dependency to the most recent version to enable support for newer Java versions (up to 17 preview).

Also fixes a bug introduced in the fix to #19, where configured smells from setTestSmells() were overwritten.
Note that this changes TestSmellDetector::setTestSmells(List<AbstractSmell> testSmells) to TestSmellDetector::setTestSmells(List<SmellFactory> testSmells) to ensure smells can be re-initialized.

[marvinkreis]

Hi. Sorry for positing this PR with no context at all. I was in a bit of a hurry when I opened it, so let me elaborate a bit:

We use TestSmellDetector over at Code Defenders to analyze user-submitted test cases and I'm currently updating our analysis to support newer Java Versions. This made it incompatible with TestSmellDetector, because our internal JavaParser version clashed with TestSmellDetector's. I don't know if you're interested in updating to a newer JavaParser version, but since I already updated it for Code Defenders I thought I might as well open an PR.

The other changes have to do with b7e1aaf (the fix to #19), which re-initialized the smells every time detectSmells() is called, ignoring which smells were configured by setTestSmells(). To fix this, I changed TestSmellDetector to save smell factories instead of smells, so it can re-initialize only the configured smells. Smells can then be set with e.g

List<SmellFactory> testSmells = new ArrayList<>();
testSmells.add(AssertionRoulette::new);
testSmells.add(DuplicateAssert::new);
detector.setTestSmells(testSmells);

instead of

List<AbstractSmell> testSmells = new ArrayList<>();
testSmells.add(new AssertionRoulette());
testSmells.add(new DuplicateAssert());
detector.setTestSmells(testSmells);