[llvm] [test] Skip some tests on Windows only (PR #95205)

[Paul T Robinson via llvm-commits]

================
@@ -1,5 +1,5 @@
-FIXME: See if we can fix this in lit by using Unicode strings.
-REQUIRES: shell
+Windows echo does not have good Unicode support.
+UNSUPPORTED: system-windows
----------------
pogo59 wrote:

FTR, the test works fine for me on Windows, unless I force it to use the gnuwin32 `echo` instead of cmd's `echo`.

Maybe use `printf` instead of `echo`? That worked in my environment.

https://github.com/llvm/llvm-project/pull/95205