[mlir] Reduce call stack depth in LogicalResult. NFC.

[kuhar]

Summary

When debuging a crash or conversion failure in a deep pass pipeline,
there are often many interleaved frames with failed and succeeded.
LogicalResult is used through the pass infrastructure, so by not implementing
failure in terms of a call to succeess, this patch noticeably reduces the total
total call stack depth and improves the debugging experience.

mlir/include/mlir/Support/LogicalResult.h

public:
   /// 'failure' result is generated.
   static LogicalResult success(bool isSuccess = true) {
     return LogicalResult(isSuccess);
   }
 
   /// If isFailure is true a `failure` result is generated, otherwise a
   /// 'success' result is generated.
   static LogicalResult failure(bool isFailure = true) {
-    return success(!isFailure);
+    return LogicalResult(!isFailure);
   }
 
   /// Returns true if the provided LogicalResult corresponds to a success value.
   bool succeeded() const { return isSuccess; }
 
   /// Returns true if the provided LogicalResult corresponds to a failure value.
-  bool failed() const { return !succeeded(); }
+  bool failed() const { return !isSuccess; }
 
 private:
   LogicalResult(bool isSuccess) : isSuccess(isSuccess) {}
 
   /// Boolean indicating if this is a success result, if false this is a
   /// failure result.
   bool isSuccess;
 };