[mlir][tensor][NFC] Remove dead code tensor.extract_slice canonicalization pattern (#131903)

Folding a cast into an `extract_slice` does not change the result type.

Author: matthias-springer

mlir/lib/Dialect/Tensor/IR/TensorOps.cpp

@@ -2476,8 +2476,6 @@ class ExtractSliceOpCastFolder final : public OpRewritePattern<ExtractSliceOp> {
         loc, sliceOp.getType(), castOp.getSource(), sliceOp.getOffsets(),
         sliceOp.getSizes(), sliceOp.getStrides(), sliceOp.getStaticOffsets(),
         sliceOp.getStaticSizes(), sliceOp.getStaticStrides());
-    if (newResult.getType() != sliceOp.getType())
-      newResult = rewriter.create<CastOp>(loc, sliceOp.getType(), newResult);
     rewriter.replaceOp(sliceOp, newResult);
     return success();
   }