Target: ChromeOS-ARM Chromebook with Mali GPU (e.g. MediaTek Kompanio
MT8195/MT8188, Mali-G57/G610). Dawn's Vulkan backend on non-Android Mali
trusts the buggy VK_KHR_zero_initialize_workgroup_memory driver
path instead of emitting Tint's explicit zeroing loop, so
var<workgroup> contains stale LDS from the previous
dispatch on the same compute unit (potentially cross-origin).
Open victim.html in a separate tab
(preferably from a different origin — the bundled server.py
serves it on port 8081). The victim repeatedly fills LDS with the sentinel
0xA5A5A5A5. This page repeatedly reads LDS before any
store and reports non-zero words.