[TensorExpr] Fix operator order in combineMultilane (#45157)
Summary:
combineMultilane used the wrong order when ramp was on the left hand side,
which matters for subtract.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/45157
Test Plan: test_tensorexpr --gtest_filter=TensorExprTest.SimplifyRampSubBroadcast
Reviewed By: ailzhang
Differential Revision: D23851751
Pulled By: asuhan
fbshipit-source-id: 864d1611e88769fb43327ef226bb3310017bf858
