[mlir][TilingInterface] Fix use after free error from D141028.

[mravishankar]

Summary

The candidateSliceOp was replaces and used in a subsequent
call. Instead just replace its uses. The op is dead and will be
removed with CSE.

mlir/include/mlir/Dialect/SCF/Transforms/TileUsingInterface.h

struct SCFTileAndFuseOptions {
   SCFTilingOptions tilingOptions;
   SCFTileAndFuseOptions &setTilingOptions(SCFTilingOptions options) {
     tilingOptions = options;
     return *this;
   }
 };
 
 /// Fuse the producer of the source of `candidateSliceOp` by computing the
-/// required slice of the producer in-place.
+/// required slice of the producer in-place.  Note that the method
+/// replaces the uses of `candidateSliceOp` with the tiled and fused producer
+/// value but does not delete the slice operation.
 struct SCFFuseProducerOfSliceResult {
   OpResult origProducer;       // Original untiled producer.
   Value tiledAndFusedProducer; // Tile and fused producer value.
 };
 std::optional<SCFFuseProducerOfSliceResult>
 tileAndFuseProducerOfSlice(RewriterBase &rewriter,
                            tensor::ExtractSliceOp candidateSliceOp,
                            MutableArrayRef<scf::ForOp> loops);

mlir/lib/Dialect/SCF/Transforms/TileUsingInterface.cpp

mlir::scf::tileAndFuseProducerOfSlice(RewriterBase &rewriter,
   // 2. Generate the tiled implementation of the producer of the source
   OpBuilder::InsertionGuard g(rewriter);
   rewriter.setInsertionPoint(candidateSliceOp);
   FailureOr<Value> fusedProducerValue =
       tensor::replaceExtractSliceWithTiledProducer(rewriter, candidateSliceOp,
                                                    fusableProducer);
   if (failed(fusedProducerValue))
     return std::nullopt;
-  rewriter.replaceOp(candidateSliceOp, fusedProducerValue.value());
+  rewriter.replaceAllUsesWith(candidateSliceOp, fusedProducerValue.value());
 
   // 3. If the slice is for a destination operand, for example,
   //
   // ```mlir
   // %0 = linalg.init
   // %1 = linalg.fill .. outs(%0 : )
   // %2 = scf.for .. iter_args(%arg0 = %1) {
   //   %3 = scf.for .. iter_args(%arg1 = %arg0) {