[clang] [clang][flang][windows] Prefer user-provided library paths (-L) (PR #90758)

[Andrzej Warzyński via cfe-commits]

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@@ -0,0 +1,8 @@
+! REQUIRES: system-windows
+!
+! RUN: %clang --driver-mode=flang -### %s -Ltest 2>&1 | FileCheck %s
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banach-space wrote:

[nit] `test` -> `random_test_dir` or something else that will make this stand out a bit more (makes parsing tests a bit easier)

https://github.com/llvm/llvm-project/pull/90758