[mlir][sparse] Fix a problem introduced by the PR for reading complex number.

[bixia]

Summary

The problem is in function isValid.

[bixia]

Rebase.

mlir/lib/ExecutionEngine/SparseTensorUtils.cpp

else if (strstr(filename, ".tns"))
       readExtFROSTTHeader();
     else
       FATAL("Unknown format %s\n", filename);
     assert(isValid() && "Failed to read the header");
   }
 
   ValueKind getValueKind() const { return valueKind_; }
 
-  bool isValid() const { return valueKind_ != ValueKind::kUndefined; }
+  bool isValid() const { return valueKind_ != ValueKind::kInvalid; }
 
   /// Gets the MME "pattern" property setting.  Is only valid after
   /// parsing the header.
   bool isPattern() const {
     assert(isValid() && "Attempt to isPattern() before readHeader()");
     return valueKind_ == ValueKind::kPattern;
   }