Disable asan for `mgpu_torch_test`
Torch throws this warning when building with asan:
UserWarning: torch.cuda: your pytorch binary has address sanitizer (asan) built in, asan is currently not compatible with torch.cuda module, you might get unexpected behavior (eg. out of memory, crash, etc.), please rebuild pytorch without asan if you need to use this module.
PiperOrigin-RevId: 818794298