[flang][runtime] Skip remainder of bad input record even with ADVANCE='NO'

[klausler]

Summary

After a recoverable error condition in a READ statement with ADVANCE='NO',
skip the remainder of the current record.

flang/runtime/io-stmt.cpp

   }
   if constexpr (DIR == Direction::Input) {
     BeginReadingRecord(); // in case there were no I/O items
-    if (mutableModes().nonAdvancing) {
+    if (mutableModes().nonAdvancing && !InError()) {
       unit().leftTabLimit = unit().furthestPositionInRecord;
-    }
-    if (!mutableModes().nonAdvancing || GetIoStat() == IostatEor) {
+    } else {
       FinishReadingRecord();
     }
   } else { // output

flang/runtime/unit.cpp

 void ExternalFileUnit::FinishReadingRecord(IoErrorHandler &handler) {
   RUNTIME_CHECK(handler, direction_ == Direction::Input && beganReadingRecord_);
   beganReadingRecord_ = false;
-  if (handler.InError() && handler.GetIoStat() != IostatEor) {
+  if (handler.GetIoStat() == IostatEnd ||
+      (IsRecordFile() && !recordLength.has_value())) {
     // Avoid bogus crashes in END/ERR circumstances; but
     // still increment the current record number so that
     // an attempted read of an endfile record, followed by
     // a BACKSPACE, will still be at EOF.
     ++currentRecordNumber;
   } else if (IsRecordFile()) {
-    RUNTIME_CHECK(handler, recordLength.has_value());
     recordOffsetInFrame_ += *recordLength;
     if (access != Access::Direct) {
       RUNTIME_CHECK(handler, isUnformatted.has_value());