Rust: Add extractor test for cfg exclusion in macro expansions

Regression test for `should_be_excluded`: items produced by a macro
expansion carrying a disabled `#[cfg(...)]` must be excluded from
extraction, just like disabled items written directly in a source file.
Uses `cfg(any())`/`cfg(all())` so the test does not depend on crate features.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 4ee033fb-30ad-4617-9922-bc0f1088ba81

Author: redsun82

rust/ql/test/extractor-tests/macro-expansion-cfg/Cargo.lock

@@ -0,0 +1,2 @@
+| cfg_macro.rs:15:1:15:15 | fn from_macro_enabled | from_macro_enabled |
+| cfg_macro.rs:21:1:22:26 | fn direct_enabled | direct_enabled |

rust/ql/test/extractor-tests/macro-expansion-cfg/cfg_macro.expected

@@ -0,0 +1,6 @@
+import rust
+import TestUtils
+
+query predicate functions(Function f, string name) {
+  toBeTested(f) and name = f.getName().getText()
+}

rust/ql/test/extractor-tests/macro-expansion-cfg/cfg_macro.ql

@@ -0,0 +1,22 @@
+// Regression test: `#[cfg(...)]`-disabled items produced by a macro expansion must be
+// excluded from extraction, just like disabled items written directly in a source file.
+// `any()` is always false and `all()` is always true, so this does not depend on crate features.
+
+macro_rules! make_cfg_items {
+    () => {
+        #[cfg(any())] // always false: must be excluded
+        pub fn from_macro_disabled() {}
+
+        #[cfg(all())] // always true: must be kept
+        pub fn from_macro_enabled() {}
+    };
+}
+
+make_cfg_items!();
+
+// Baseline: the same predicates on items written directly in the file (not via a macro).
+#[cfg(any())] // always false: must be excluded
+pub fn direct_disabled() {}
+
+#[cfg(all())] // always true: must be kept
+pub fn direct_enabled() {}