test: strengthen regression oracles and cleanup ownership (#8152)

* test: strengthen suite oracles and cleanup ownership

* test: reuse setup across independent scenarios (#8153)

* Potential fix for pull request finding 'CodeQL / Improper code sanitization'

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

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Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

src/domain/javascript/javascriptSymbolicBindings.test.ts

@@ -631,6 +631,7 @@ it("propagates branch guards through object properties and function calls", () =
     inspect(direct.action);
     inspect(called.action);
   `);
+  expect(inspected).toHaveLength(2);
   for (const value of inspected) {
     const functions = symbolicVariants(value).filter(
       (candidate) => candidate.kind === "function",