Use StreamEvaluator in repair

src/main/scala/leon/evaluators/AngelicEvaluator.scala

src/main/scala/leon/evaluators/DefaultEvaluator.scala

src/main/scala/leon/evaluators/DualEvaluator.scala

src/main/scala/leon/evaluators/Evaluator.scala

src/main/scala/leon/evaluators/EvaluatorContexts.scala

src/main/scala/leon/evaluators/RecursiveEvaluator.scala

src/main/scala/leon/evaluators/StreamEvaluator.scala

src/main/scala/leon/purescala/ExprOps.scala

src/main/scala/leon/repair/RepairNDEvaluator.scala

src/main/scala/leon/repair/RepairTrackingEvaluator.scala

src/main/scala/leon/repair/rules/Focus.scala

src/main/scala/leon/utils/StreamUtils.scala

src/test/resources/regression/repair/Heap3.scala

...st/scala/leon/integration/evaluators/EvaluatorSuite.scala

src/test/scala/leon/regression/repair/RepairSuite.scala

src/test/scala/leon/unit/evaluators/EvaluatorSuite.scala