[pallas] Add more test cases for Triton bitcast_convert_type lowering rule.

PiperOrigin-RevId: 698818103

Author: petebu

tests/pallas/ops_test.py

@@ -1941,9 +1941,13 @@ def kernel(x_ref, out_ref):
 
   @parameterized.parameters(
       (jnp.float16, jnp.float16),  # Noop
-      (jnp.int16, jnp.float16),
       (jnp.int16, jnp.bfloat16),
+      (jnp.int16, jnp.float16),
+      (jnp.uint16, jnp.float16),
       (jnp.float32, jnp.int32),
+      (jnp.float32, jnp.uint32),
+      (jnp.uint32, jnp.int32),
+      (jnp.int32, jnp.uint32),
   )
   def test_bitcast_convert_type(self, in_dtype, out_dtype):
     if jtu.test_device_matches(["tpu"]):