Remove BUNLDER_VERSION in Windows (#3859)

[Bug #17372]

.github/workflows/mingw.yml

@@ -107,7 +107,8 @@ jobs:
           [Console]::OutputEncoding = [System.Text.Encoding]::GetEncoding("IBM437")
           [Console]::InputEncoding  = [System.Text.Encoding]::GetEncoding("IBM437")
           $jobs = [int](1.5 * $env:NUMBER_OF_PROCESSORS)
-          make test-all TESTOPTS="-j $jobs --retry --job-status=normal --show-skip --timeout-scale=1.5 --regexp=\"!/^(test_to_specs_respects_bundler_version|test_gem_bundler|test_activate_bin_path_gives_proper_error_for_bundler)$/\""
+          if ($env:BUNDLER_VERSION) { Remove-Item env:\BUNDLER_VERSION }
+          make test-all TESTOPTS="-j $jobs --retry --job-status=normal --show-skip --timeout-scale=1.5"
 
       - name: test-spec
         timeout-minutes: 10