Improve Windows CI

[ndabas]

Following on from #6091. A few improvements for the Windows side of things:

• The Windows_clang_cmake, Windows_flang_clang and Windows_cl_flang jobs were silently failing (examples: 1, 2, 3) in Azure pipelines:
  • I changed the shell to PowerShell and set stop-on-error.
  • Visual Studio paths are now found with with vswhere.
  • The flang package did not include runtime libraries so added flang-rt_win-64.
  • Made sure that something is tested with ctest --no-tests=error.
• I added a new workflow, .github/workflows/windows_make_install.yml to test for OpenBLASConfig.cmake from the Makefile build on Windows has no OpenBLAS::OpenBLAS target: echo lines are missing the redirect #6084. Let me know if you would rather fold this into the existing Windows ARM64 workflow (and call that windows.yml instead.)
• I added CLARNGARM64 to the msys2 job in .github/workflows/dynamic_arch.yml.

[martin-frbg]

Quick question, didn't look closely - There's a dedicated workflow for windows-on-arm, does the added job do something different ?

[ndabas]

Quick question, didn't look closely - There's a dedicated workflow for windows-on-arm, does the added job do something different ?

Yes, that job runs a configure/build/test with Visual Studio, only on Windows ARM64. I guess that was added as a separate workflow because Azure Pipelines does not currently support Windows ARM64.

The new job does have a bit of overlap with this one, bit it also runs on Windows x64 in addition to ARM64, and runs make install as well.

This is why I suggested that we fold both into a single workflow, let me know if that sounds like a better idea -- I'll go ahead and do that.

[ndabas]

Of course it's up to you if you would like to keep all of these changes -- if the added workflow doesn't make sense, I can remove that commit and we can keep only the Azure pipelines fixes (azure-pipelines.yml) and the CLANGARM64 addition (.github/workflows/dynamic_arch.yml).