[SPIR-V] Switch operands might depends on pointer allocation pattern

[Keenuts]

By adding #92531, I added a new potential source or test flakiness: seems like the order of the switch operands might depend on a SmallPtrSet, hence on memory allocation pattern.

[llvmbot]

@llvm/issue-subscribers-bug

Author: Nathan Gauër (Keenuts)

By adding https://github.com//pull/92531, I added a new potential source or test flakiness: seems like the order of the switch operands might depend on a SmallPtrSet, hence on memory allocation pattern.