Macos Arm64 nightly binaries are failing since 09.28.2024

[atalman]

🐛 Describe the bug

Both conda and wheels nightly binaries are failing:
https://hud2.pytorch.org/hud/pytorch/pytorch/nightly/1?per_page=50&name_filter=macos-arm64

Error:

mmacosx-version-min=10.15 -fPIC -DTORCH_USE_LIBUV -DCAFFE2_USE_GLOO -D__NEON__ -O2 -MD -MT caffe2/CMakeFiles/torch_cpu.dir/__/aten/src/ATen/native/mps/operations/Distributions.mm.o -MF caffe2/CMakeFiles/torch_cpu.dir/__/aten/src/ATen/native/mps/operations/Distributions.mm.o.d -o caffe2/CMakeFiles/torch_cpu.dir/__/aten/src/ATen/native/mps/operations/Distributions.mm.o -c /Users/runner/work/pytorch/pytorch/pytorch/aten/src/ATen/native/mps/operations/Distributions.mm
2024-09-29T08:20:45.4831870Z /Users/runner/work/pytorch/pytorch/pytorch/aten/src/ATen/native/mps/operations/Distributions.mm:88:20: error: use of undeclared identifier 'MPSDataTypeBFloat16'; did you mean 'MPSDataTypeFloat16'?
2024-09-29T08:20:45.4934510Z             return MPSDataTypeBFloat16;
2024-09-29T08:20:45.5036300Z                    ^~~~~~~~~~~~~~~~~~~
2024-09-29T08:20:45.5138000Z                    MPSDataTypeFloat16
2024-09-29T08:20:45.5243220Z /Applications/Xcode_14.3.1.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX13.3.sdk/System/Library/Frameworks/MetalPerformanceShaders.framework/Frameworks/MPSCore.framework/Headers/MPSCoreTypes.h:239:5: note: 'MPSDataTypeFloat16' declared here
2024-09-29T08:20:45.5347790Z     MPSDataTypeFloat16  MPS_ENUM_AVAILABLE_STARTING( macos(10.13), ios(11.0), macCatalyst(13.0), tvos(11.0)) = MPSDataTypeFloatBit | 16,
2024-09-29T08:20:45.5449330Z     ^
2024-09-29T08:20:45.5550710Z 1 error generated.

Versions

2.6.0 nightly

cc @seemethere @malfet @osalpekar

[malfet]

Must be a regression caused by one of my PRs, fix is coming, though we should really figure out how to detect those earlier...