LibJS: Convert all remaining non-Array tests to the new system :)

Author: https://github.com/mattco98
Commit: 15de2eda2b
Pull-request: https://github.com/SerenityOS/serenity/pull/2689
Reviewed-by: https://github.com/linusg

Libraries/LibJS/Tests/loops/continue-basic.js

@@ -1,11 +1,10 @@
-load("test-common.js");
-
-try {
+test("basic functionality", () => {
   var j = 0;
   for (var i = 0; i < 9; ++i) {
-    if (i == 3) continue;
+    if (i == 3) {
+      continue;
+    }
     ++j;
   }
-  assert(j == 8);
-  console.log("PASS");
-} catch {}
+  expect(j).toBe(8);
+});