Implement asInstanceOf

...tegration/scala/leon/test/evaluators/EvaluatorSuite.scala

src/integration/scala/leon/test/purescala/ExprOpsSuite.scala

src/main/scala/leon/codegen/CodeGeneration.scala

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

src/main/scala/leon/frontends/scalac/ASTExtractors.scala

src/main/scala/leon/frontends/scalac/CodeExtraction.scala

src/main/scala/leon/purescala/Constructors.scala

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

src/main/scala/leon/purescala/Expressions.scala

src/main/scala/leon/purescala/Extractors.scala

src/main/scala/leon/purescala/PrettyPrinter.scala

src/main/scala/leon/purescala/TypeOps.scala

...main/scala/leon/solvers/combinators/UnrollingSolver.scala

src/main/scala/leon/solvers/smtlib/SMTLIBSolver.scala

src/main/scala/leon/solvers/templates/UnrollingBank.scala

src/main/scala/leon/solvers/z3/AbstractZ3Solver.scala

src/main/scala/leon/solvers/z3/FairZ3Solver.scala

src/main/scala/leon/synthesis/Rules.scala

src/main/scala/leon/synthesis/rules/EquivalentInputs.scala

src/main/scala/leon/termination/SelfCallsProcessor.scala