asuint.64.test fails on warp

Nobody has claimed this yet.

The output buffer looks to fail in the exact same way as https://github.com/llvm/offload-test-suite/issues/398
```yml
# .---command stdout------------
# | Using DirectX API
# | Configuring execution on device: Microsoft Basic Render Driver
# | RootSignature created.
# | Descriptor heap created.
# | PSO created.
# | Command structures created.
# | Creating SRV: { Size = 96, Register = t0, Space = 0 }
# | Creating UAV: { Size = 64, Register = u1, Space = 0, HasCounter = 0 }
# | Creating UAV: { Size = 64, Register = u2, Space = 0, HasCounter = 0 }
# | EltSize = 32 NumElts = 3
# | SRV: HeapIdx = 0 EltSize = 32 NumElts = 3
# | EltSize = 16 NumElts = 4
# | UAV: HeapIdx = 1 EltSize = 16 NumElts = 4 HasCounter = 0
# | EltSize = 16 NumElts = 4
# | UAV: HeapIdx = 2 EltSize = 16 NumElts = 4 HasCounter = 0
# | Buffers created.
# | Event prepared.
# | Compute command list created.
# | Compute commands executed.
# | Read data back.
# `-----------------------------
# .---command stderr------------
# | Test failed: Test0
# | Comparison Rule: BufferExact
# | Expected:
# | ---
# | Name: ExpectedLows
# | Format: UInt32
# | Stride: 16
# | Data: [ 0, 0, 343597384, 2680059593, 0, 2576980378, 2576980378,
# | 1717986918, 858993459, 2696277389, 3944497965, 2680059593,
# | 0, 0, 536870912, 2684354560 ]
# | OutputProps:
# | Height: 0
# | Width: 0
# | Depth: 0
# | ...
# | Got:
# | ---
# | Name: Lows
# | Format: UInt32
# | Stride: 16
# | Data: [ 0, 0, 343597384, 2680059593, 0, 2576980378, 2576980378,
# | 1717986918, 858993459, 2696277389, 3944497965, 2680059593,
# | 0, 0, 343597384, 2680059593 ]
# | OutputProps:
# | Height: 0
# | Width: 0
# | Depth: 0
# | ...
# | Full Hex 64bit representation of Expected Buffer Values:
# | [ 0x0, 0x0, 0x147ae148, 0x9fbe76c9, 0x0, 0x9999999a, 0x9999999a, 0x66666666, 0x33333333, 0xa0b5ed8d, 0xeb1c432d, 0x9fbe76c9, 0x0, 0x0, 0x20000000, 0xa0000000 ]
# | Full Hex 64bit representation of Actual Buffer Values:
# | [ 0x0, 0x0, 0x147ae148, 0x9fbe76c9, 0x0, 0x9999999a, 0x9999999a, 0x66666666, 0x33333333, 0xa0b5ed8d, 0xeb1c432d, 0x9fbe76c9, 0x0, 0x0, 0x147ae148, 0x9fbe76c9 ]
# |
# `-----------------------------
# error: command failed with exit status: 1

--
```

Start with the asuint.64.test case and reproduce it on warp using the command output shown. Compare ExpectedLows with Lows and consult issue 398 for the related output-buffer failure; done when the test passes with the expected values.

Written by the indexing model from the issue text.