Add zeros initialization to failing smem-hbm copy test.

tests/pallas/pallas_call_tpu_test.py

@@ -900,9 +900,10 @@ def body(x_ref, sem):
   def test_smem_hbm_dma(self):
     def kernel(x_ref, y_hbm_ref):
       def body(y_ref, sem):
-        y_ref[0, 0] = x_ref[4, 4]
+        y_ref[0, 0] = 0.0
+        y_ref[0, 1] = x_ref[4, 4]
         pltpu.async_copy(y_ref, y_hbm_ref, sem).wait()
-      pltpu.run_scoped(body, pltpu.SMEM((8, 128), jnp.float32),
+      pltpu.run_scoped(body, pltpu.SMEM((1, 2), jnp.float32),
                        pltpu.SemaphoreType.DMA)
     x = jnp.arange(8 * 128.).reshape((8, 128))
     y = pl.pallas_call(
@@ -911,9 +912,9 @@ def body(y_ref, sem):
             pl.BlockSpec(memory_space=pltpu.TPUMemorySpace.SMEM),
         ],
         out_specs=pl.BlockSpec(memory_space=pltpu.TPUMemorySpace.ANY),
-        out_shape=jax.ShapeDtypeStruct((8, 128), jnp.float32),
+        out_shape=jax.ShapeDtypeStruct((1, 2), jnp.float32),
     )(x)
-    expected = jnp.zeros_like(x).at[0, 0].set(x[4, 4])
+    expected = jnp.zeros_like(x[0:1, 0:2]).at[0, 1].set(x[4, 4])
     np.testing.assert_allclose(y, expected)
 
   def test_vmem_vmem_dma(self):