[flang][runtime] Don't raise internal error in user error recovery situation

[klausler]

Summary

In the case of a data transfer I/O statement with an illegal unit number and
error recovery, ensure that data transfer API calls don't raise internal
errors due to the I/O statement representation unexpectedly being something
other than a data transfer statement.

flang/runtime/io-stmt.h

std::optional<char32_t> GetNextNonBlank(std::size_t &byteCount) {
     }
     return ch;
   }
 
   template <Direction D> bool CheckFormattedStmtType(const char *name) {
     if (get_if<FormattedIoStatementState<D>>()) {
       return true;
     } else {
-      if (!get_if<ErroneousIoStatementState>()) {
-        GetIoErrorHandler().Crash(
-            "%s called for I/O statement that is not formatted %s", name,
-            D == Direction::Output ? "output" : "input");
+      auto &handler{GetIoErrorHandler()};
+      if (!handler.InError()) {
+        handler.Crash("%s called for I/O statement that is not formatted %s",
+            name, D == Direction::Output ? "output" : "input");
       }
       return false;
     }
   }
 
 private:
   std::variant<std::reference_wrapper<OpenStatementState>,
       std::reference_wrapper<CloseStatementState>,