GHA: Fix MinGW test

Using `bash` puts `/mingw64/bin` first in the path but the compiler from
`/c/mingw64/bin` is used.
This leads to errors running the tests: "Exit code 0xc0000139" (DLL issue)
which are related to the use of `thread_local`.
Using the powershell works in all cases.

.github/workflows/ci_tests.yml

@@ -106,12 +106,14 @@ jobs:
       run: cmake --build build --config ${{matrix.buildType}} --target tests
 
     # Run test with both bash and powershell and watch for "Using std::cin" on bash but not on powershell
+    # Except for MinGW where the bash shell makes it use the wrong DLLs
     - name: Test
       working-directory: build
+      if: "! (runner.os == 'Windows' && endsWith(matrix.generator, 'Makefiles'))"
       run: ctest --output-on-failure -C ${{matrix.buildType}} --verbose
     - name: Test on PowerShell
       working-directory: build
-      shell: powershell
+      shell: pwsh
       if: runner.os == 'Windows'
       run: ctest --output-on-failure -C ${{matrix.buildType}} --verbose