Reset operation when canceling root update transaction

[cathyzhyi]

Summary

Should reset the operation to original state when canceling the updates.

[ftynse]

LGTM. Please wait for @rriddle to double-check.

mlir/lib/Transforms/Utils/DialectConversion.cpp

#ifndef NDEBUG
   assert(impl->pendingRootUpdates.erase(op) &&
          "operation did not have a pending in-place update");
 #endif
   // Erase the last update for this operation.
   auto stateHasOp = [op](const auto &it) { return it.getOperation() == op; };
   auto &rootUpdates = impl->rootUpdates;
   auto it = llvm::find_if(llvm::reverse(rootUpdates), stateHasOp);
   assert(it != rootUpdates.rend() && "no root update started on op");
+  (*it).resetOperation();
   int updateIdx = std::prev(rootUpdates.rend()) - it;
   rootUpdates.erase(rootUpdates.begin() + updateIdx);
 }
 
 /// PatternRewriter hook for notifying match failure reasons.
 LogicalResult ConversionPatternRewriter::notifyMatchFailure(
     Operation *op, function_ref<void(Diagnostic &)> reasonCallback) {
   return impl->notifyMatchFailure(op->getLoc(), reasonCallback);