Clean pending exception before running dynamic CDS dump

The following two "if" blocks should be swapped. Otherwise a pre-existing exception may cause MetaspaceShared::link_and_cleanup_shared_classes() to fail.

void JavaThread::invoke_shutdown_hooks() {
  HandleMark hm(this);

  // Link all classes for dynamic CDS dumping before vm exit.
  // Same operation is being done in JVM_BeforeHalt for handling the
  // case where the application calls System.exit().
  if (DynamicDumpSharedSpaces) {
    MetaspaceShared::link_and_cleanup_shared_classes(this);
  }

  // We could get here with a pending exception, if so clear it now.
  if (this->has_pending_exception()) {
    this->clear_pending_exception();
  }