[llvm] [LLVM][Examples][Cygwin] Exclude examples that are not built from test dependencies (PR #172145)

[Alexis Engelke via llvm-commits]

aengelke wrote:

I think you also should adjust llvm/test/Examples/lit.local.cfg to include cygwin and not just win32. It might happen to work without right now because LLVM isn't built as shared library, which disables plugins.

https://github.com/llvm/llvm-project/pull/172145