Make compiletest setup consistent with serde_json

test_suite/tests/compiletest.rs

@@ -4,7 +4,7 @@ use compiletest_rs as compiletest;
 
 #[test]
 fn ui() {
-    let config = compiletest::Config {
+    compiletest::run_tests(&compiletest::Config {
         mode: compiletest::common::Mode::Ui,
         src_base: std::path::PathBuf::from("tests/ui"),
         target_rustcflags: Some(String::from(
@@ -16,7 +16,5 @@ fn ui() {
              ",
         )),
         ..Default::default()
-    };
-
-    compiletest::run_tests(&config);
+    });
 }