Unfortunately, currently, the analyzer core sets the checker name after the constructor was already run. So if we set the BugType in the constructor, the output plist will not contain a checker name. Right now the idiomatic solution is to create the BugType lazily. This patch updates the SimpleStreamChecker to follow this idiom.
In the future probably it would be better to alter the signature of the checkers and set the checker name in the constructor so it is possible to create the BugType eagerly.