Flaky hip command_buffer_dispatch tests returning all 0s

[ScottTodd]

What happened?

Some tests have started failing on and off, with logs like these:

• https://github.com/iree-org/iree/actions/runs/13444348294/job/37566558042
• https://github.com/iree-org/iree/actions/runs/13448729921/job/37579537431

5/186 Test   #60: iree/hal/drivers/hip/cts/hip_stream_command_buffer_dispatch_constants_test .......................***Failed    1.12 sec
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from CommandBufferDispatchConstantsTest
[ RUN      ] CommandBufferDispatchConstantsTest.DispatchWithDispatchConstants
iree/runtime/src/iree/hal/cts/command_buffer_dispatch_constants_test.h:124: Failure
Value of: output_data
Expected: equals { 11, 22, 33, [44](https://github.com/iree-org/iree/actions/runs/13448729921/job/37579537431#step:11:45) }
  Actual: { 0, 0, 0, 0 }, which has these unexpected elements: 0, 0, 0, 0,
and doesn't have these expected elements: 11, 22, 33, 44

[  FAILED  ] CommandBufferDispatchConstantsTest.DispatchWithDispatchConstants (10 ms)

These are all the tests that failed, each in a similar way:

The following tests FAILED:
Errors while running CTest
	 60 - iree/hal/drivers/hip/cts/hip_stream_command_buffer_dispatch_constants_test (Failed)
	 69 - iree/hal/drivers/hip/cts/hip_graph_command_buffer_dispatch_constants_test (Failed)
	 78 - iree/hal/drivers/hip/cts/hip_multi_queue_stream_command_buffer_dispatch_constants_test (Failed)
	 87 - iree/hal/drivers/hip/cts/hip_multi_queue_graph_command_buffer_dispatch_constants_test (Failed)
	 96 - iree/hal/drivers/hip/cts/hip_multi_queue_stream_queue_1_command_buffer_dispatch_constants_test (Failed)
	105 - iree/hal/drivers/hip/cts/hip_multi_queue_graph_queue_1_command_buffer_dispatch_constants_test (Failed)

Steps to reproduce your issue

1. Build with ROCm/HIP enabled
2. Run ctest

What component(s) does this issue relate to?

Runtime

Version information

Observed on fb3523b and 308d176.

There were recent changes to https://github.com/iree-org/iree/commits/main/runtime/src/iree/hal/drivers/hip that look relevant:

• 3c14d0d
• 8947738
• 7e62e5f
• 6c07258

Additional context

So far only seeing this on MI300 CI bots in this test_mi300 job, which have other ongoing infrastructure issues that make spotting these flakes harder: #19955.