[BatchMode] Add virtual destructor to Job.

include/swift/Driver/Job.h

@@ -236,6 +236,8 @@ public:
         ExtraEnvironment(std::move(ExtraEnvironment)),
         FilelistFileInfos(std::move(Infos)) {}
 
+  virtual ~Job();
+
   const JobAction &getSource() const {
     return *SourceAndCondition.getPointer();
   }

lib/Driver/Job.cpp

@@ -181,6 +181,7 @@ CommandOutput::dump() const {
   llvm::errs() << '\n';
 }
 
+Job::~Job() = default;
 
 void Job::printArguments(raw_ostream &os,
                          const llvm::opt::ArgStringList &Args) {