Executable model doesn't work on Windows

After these changes [1], executable model stopped working on Windows. The problem is that our memory file system cannot use Windows file separator as is used here [2].

[1] https://github.com/kiegroup/drools/commit/d22c958f04ff8b77d0e10608bca35c8b516a5f29
[2] https://github.com/kiegroup/drools/blob/d22c958f04ff8b77d0e10608bca35c8b516a5f29/drools-model/drools-model-compiler/src/main/java/org/drools/modelcompiler/CanonicalKieModule.java#L679