Windows cuda export ci and set up script

[JacobSzwejbka]

Add a script that tries to auto install mingw and the windows cuda rt. Sets up WINDOWS_CUDA_HOME as well for now though we should probably move away from using random env variables for stuff like this...

To test add some export stuff to CI. Just verify that export and lowering succeeds against the usual suspects. A follow up will spin up some windows + cuda machines and try running whisper and voxtral.

[pytorch-bot]

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❌ 1 New Failure, 1 Cancelled Job, 1 Unrelated Failure

As of commit 0e760f9 with merge base 7fa1aaa ():

NEW FAILURE - The following job has failed:

• trunk / test-models-macos-cpu (ic4, xnnpack-quantization-delegation) / macos-job (gh)
  RuntimeError: Command bash /Users/ec2-user/runner/_work/_temp/exec_script failed with exit code 2

CANCELLED JOB - The following job was cancelled. Please retry:

• pull / unittest-buck / macos / macos-job (gh)
  ##[error]The operation was canceled.

UNSTABLE - The following job is marked as unstable, possibly due to flakiness on trunk:

• pull / android / run-emulator (gh) (#16137)
  Timeout waiting for emulator to boot.

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