test: use olive-render-worker.exe on Windows in render worker footage test

QFileInfo::exists() does not auto-append .exe on Windows, so the test
failed to locate the worker binary even though it was built.

tests/gtest/render_worker_footage_test.cpp

@@ -99,7 +99,11 @@ QString WorkerBinaryPath()
 	dir.cdUp();  // tests/gtest -> tests
 	dir.cdUp();  // tests -> build dir
 	dir.cd(QStringLiteral("app"));
+#if defined(_WIN32)
+	return dir.filePath(QStringLiteral("olive-render-worker.exe"));
+#else
 	return dir.filePath(QStringLiteral("olive-render-worker"));
+#endif
 }
 
 QString DemoVideoPath()