[flang] Allow user to recover from bad edit descriptor with INTEGER

[jeanPerier]

Summary

Runtime was crashing when an INTEGER passed in formatted output with
a bad edit descriptor even when the user did provide IOSTAT. Flang
is already signaling an error when facing similar error with other
types. Do the same with INTEGERs.

The input case is already signaling an error in the related input error
case.

flang/runtime/edit-output.cpp

for (; un > 0; un >>= 4) {
       int digit = static_cast<int>(un) & 0xf;
       *--p = digit >= 10 ? 'A' + (digit - 10) : '0' + digit;
     }
     break;
   case 'A': // legacy extension
     return EditCharacterOutput(
         io, edit, reinterpret_cast<char *>(&n), sizeof n);
   default:
-    io.GetIoErrorHandler().Crash(
+    io.GetIoErrorHandler().SignalError(IostatErrorInFormat,
         "Data edit descriptor '%c' may not be used with an INTEGER data item",
         edit.descriptor);
     return false;
   }
 
   int digits = end - p;
   int leadingZeroes{0};
   int editWidth{edit.width.value_or(0)};