Test 8 fails on Windows

[lefessan]

From https://github.com/OCamlPro/gnucobol/actions/runs/6675975179?pr=109

8. used_binaries.at:350: testing temporary path invalid ...
../../tests/used_binaries.at:366: TMPDIR="" TMP="notthere" TEMP="" $COMPILE prog.cob
--- -   2023-10-28 09:10:22.004766600 +0000
+++ /d/a/gnucobol/gnucobol/_build/tests/testsuite.dir/at-groups/8/stderr        2023-10-28 09:10:21.922287300 +0000
@@ -1,2 +1,3 @@
 libcob: warning: Temporary directory TMP is invalid, adjust TMPDIR!
+Cannot create temporary file in: Invalid argument
 
../../tests/used_binaries.at:366: exit code was 1, expected 0
8. used_binaries.at:350: 8. temporary path invalid (used_binaries.at:350): FAILED (used_binaries.at:366)

[ddeclerck]

This is a known issue with the temporary PATH on Windows. I'll check if something can be done about it.