[flang] Fix INQUIRE of access and formatting possibilities

[klausler]

Summary

Don't give false positives from INQUIRE about possible
access mode changes on connected units. DIRECT and SEQUENTIAL
cannot be intermixed, apart from allowing DIRECT on a SEQUENTIAL
file with fixed-size records and positioning. Nor can
FORMATTED and UNFORMATTED be interchanged. On unconnected
files, the best that we can do is "UNKNOWN".

[PeteSteinfeld]

All builds, tests, and looks good.

flang/runtime/io-stmt.cpp

if (unit().isUnformatted) {
         break;
       default:
         str = "NONE";
         break;
       }
     }
     break;
   case HashInquiryKeyword("DIRECT"):
-    str = unit().mayPosition() ? "YES" : "NO";
+    str = unit().access == Access::Direct ||
+            (unit().mayPosition() && unit().isFixedRecordLength)
+        ? "YES"
+        : "NO";
     break;
   case HashInquiryKeyword("ENCODING"):
     str = unit().isUnformatted ? "UNDEFINED"
         : unit().isUTF8        ? "UTF-8"
                                : "ASCII";
     break;
   case HashInquiryKeyword("FORM"):
     str = unit().isUnformatted ? "UNFORMATTED" : "FORMATTED";
     break;
   case HashInquiryKeyword("FORMATTED"):
-    str = "YES";
+    str = !unit().isUnformatted ? "YES" : "NO";
     break;
   case HashInquiryKeyword("NAME"):
     str = unit().path();
     if (!str) {
       return true; // result is undefined
     }
     break;
   case HashInquiryKeyword("PAD"):
if (unit().isUnformatted) {
         break;
       case decimal::FortranRounding::RoundCompatible:
         str = "COMPATIBLE";
         break;
       }
     }
     break;
   case HashInquiryKeyword("SEQUENTIAL"):
-    str = "YES";
+    // "NO" for Direct, since Sequential would not work if
+    // the unit were reopened without RECL=.
+    str = unit().access == Access::Sequential ? "YES" : "NO";
     break;
   case HashInquiryKeyword("SIGN"):
     str = unit().isUnformatted                 ? "UNDEFINED"
         : unit().modes.editingFlags & signPlus ? "PLUS"
                                                : "SUPPRESS";
     break;
   case HashInquiryKeyword("STREAM"):
-    str = "YES";
+    str = unit().access == Access::Stream ? "YES" : "NO";
     break;
   case HashInquiryKeyword("WRITE"):
     str = unit().mayWrite() ? "YES" : "NO";
     break;
   case HashInquiryKeyword("UNFORMATTED"):
-    str = "YES";
+    str = unit().isUnformatted ? "YES" : "NO";
     break;
   }
   if (str) {
     ToFortranDefaultCharacter(result, length, str);
     return true;
   } else {
     BadInquiryKeywordHashCrash(inquiry);
     return false;
bool InquireUnconnectedFileState::Inquire(
   case HashInquiryKeyword("PAD"):
   case HashInquiryKeyword("POSITION"):
   case HashInquiryKeyword("ROUND"):
   case HashInquiryKeyword("SIGN"):
     str = "UNDEFINED";
     break;
   case HashInquiryKeyword("DIRECT"):
   case HashInquiryKeyword("ENCODING"):
+  case HashInquiryKeyword("FORMATTED"):
+  case HashInquiryKeyword("SEQUENTIAL"):
+  case HashInquiryKeyword("STREAM"):
+  case HashInquiryKeyword("UNFORMATTED"):
     str = "UNKNONN";
     break;
   case HashInquiryKeyword("READ"):
     str = MayRead(path_.get()) ? "YES" : "NO";
     break;
   case HashInquiryKeyword("READWRITE"):
     str = MayReadAndWrite(path_.get()) ? "YES" : "NO";
     break;
   case HashInquiryKeyword("WRITE"):
     str = MayWrite(path_.get()) ? "YES" : "NO";
     break;
-  case HashInquiryKeyword("FORMATTED"):
-  case HashInquiryKeyword("SEQUENTIAL"):
-  case HashInquiryKeyword("STREAM"):
-  case HashInquiryKeyword("UNFORMATTED"):
-    str = "YES";
-    break;
   case HashInquiryKeyword("NAME"):
     str = path_.get();
     return true;
   }
   if (str) {
     ToFortranDefaultCharacter(result, length, str);
     return true;
   } else {