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/variable-undefined.js

@@ -1,14 +1,14 @@
 test("basic functionality", () => {
-  function foo(a) {
-    return a;
-  }
+    function foo(a) {
+        return a;
+    }
 
-  var x = undefined;
-  expect(x).toBeUndefined();
-  expect(foo(x)).toBeUndefined();
+    var x = undefined;
+    expect(x).toBeUndefined();
+    expect(foo(x)).toBeUndefined();
 
-  var o = {};
-  o.x = x;
-  expect(o.x).toBeUndefined();
-  expect(o.x).toBe(x);
+    var o = {};
+    o.x = x;
+    expect(o.x).toBeUndefined();
+    expect(o.x).toBe(x);
 });