add non-regression test for issue 127052

tests/ui/linkage-attr/unreferenced-used-static-issue-127052.rs

@@ -0,0 +1,9 @@
+// This is a non-regression test for issue #127052 where unreferenced `#[used]` statics couldn't be
+// removed by the MSVC linker, causing linking errors.
+
+//@ build-pass: needs linking
+//@ only-msvc
+
+#[used]
+static FOO: u32 = 0;
+fn main() {}