Revert "deps: Update to mimalloc 3.5.2"

[spencer-lunarg]

This reverts commit 27c7f10

CI is not happy with the update, forgot to run, will need to figure out

hitting errors like

ERROR: return code 3 (0x3) - details on failing tests follow
ERROR: ----stderr---------------------------------------------------
mimalloc: assertion failed: at "C:\j\vz1\Debug64\Vulkan-ValidationLayers\external\Debug\64\mimalloc\src\alloc.c":278, mi_theap_malloc
  assertion: "theap!=NULL"
mimalloc: assertion failed: at "C:\j\vz1\Debug64\Vulkan-ValidationLayers\external\Debug\64\mimalloc\src\alloc.c":278, mi_theap_malloc
  assertion: "theap!=NULL"
ERROR: -------------------------------------------------------------

[ci-tester-lunarg]

CI Vulkan-ValidationLayers build queued with queue ID 124502.