LibJS: Indent tests with 4 spaces instead of 2

Author: https://github.com/mattco98
Commit: 1ef573eb30
Pull-request: https://github.com/SerenityOS/serenity/pull/2689
Reviewed-by: https://github.com/linusg

Libraries/LibJS/Tests/builtins/JSON/JSON.stringify-proxy.js

@@ -1,11 +1,11 @@
 test("basic functionality", () => {
-  let p = new Proxy([], {
-    get(_, key) {
-      if (key === "length") return 3;
-      return Number(key);
-    },
-  });
+    let p = new Proxy([], {
+        get(_, key) {
+            if (key === "length") return 3;
+            return Number(key);
+        },
+    });
 
-  expect(JSON.stringify(p)).toBe("[0,1,2]");
-  expect(JSON.stringify([[new Proxy(p, {})]])).toBe("[[[0,1,2]]]");
+    expect(JSON.stringify(p)).toBe("[0,1,2]");
+    expect(JSON.stringify([[new Proxy(p, {})]])).toBe("[[[0,1,2]]]");
 });