Integrate llvm/torch-mlir@66bac5f (#24168)

Picks up https://github.com/llvm/torch-mlir/pull/4538 to unblock
Fusilli's IREE bump.



ci-extra: test_torch

Signed-off-by: Ian Wood <ianwood@u.northwestern.edu>

third_party/torch-mlir

diff --git a/third_party/torch-mlir b/third_party/torch-mlir
index 278ba3a..66bac5f 160000
--- a/third_party/torch-mlir
+++ b/third_party/torch-mlir
@@ -1 +1 @@
-Subproject commit 278ba3a96eec3266fb11e36bb600fdc197a35cc8
+Subproject commit 66bac5fcc6bcb0050eef5b0edddf1a50d1440c0f