Windows CI always builds llvm-project

[gongsu832]

It appears that Windows CI is failing to find the cached and therefore always rebuilds llvm-project. This makes the build take almost 4 hours to finish.

2023-09-05T18:03:37.0764952Z ##[section]Starting: Check for mlir artifact
2023-09-05T18:03:37.0873571Z ==============================================================================
2023-09-05T18:03:37.0873717Z Task         : PowerShell
2023-09-05T18:03:37.0873784Z Description  : Run a PowerShell script on Linux, macOS, or Windows
2023-09-05T18:03:37.0873895Z Version      : 2.226.2
2023-09-05T18:03:37.0873963Z Author       : Microsoft Corporation
2023-09-05T18:03:37.0874041Z Help         : https://docs.microsoft.com/azure/devops/pipelines/tasks/utility/powershell
2023-09-05T18:03:37.0874145Z ==============================================================================
2023-09-05T18:03:38.0697494Z Generating script.
2023-09-05T18:03:38.1116486Z ========================== Starting Command Output ===========================
2023-09-05T18:03:38.1356537Z ##[command]"C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe" -NoLogo -NoProfile -NonInteractive -ExecutionPolicy Unrestricted -Command ". 'D:\a\_temp\c6201e30-a2ee-4f59-abe5-3fd607debe63.ps1'"
2023-09-05T18:04:53.7329503Z Found build NotFound containing artifact MLIR_Windows_91088978d712cd7b33610c59f69d87d5a39e3113
2023-09-05T18:04:53.8304662Z ##[section]Finishing: Check for mlir artifact