test-js: Use prettier and format all files

Author: https://github.com/mattco98
Commit: 6d58c48c2f
Pull-request: https://github.com/SerenityOS/serenity/pull/2689
Reviewed-by: https://github.com/linusg

Libraries/LibJS/Tests/update-expression-on-member-expression.js

@@ -1,8 +1,8 @@
 test("basic update expression", () => {
-    var o = {};
-    o.f = 1;
+  var o = {};
+  o.f = 1;
 
-    expect(o.f++).toBe(1);
-    expect(++o.f).toBe(3);
-    expect(++o.missing).toBeNaN();
+  expect(o.f++).toBe(1);
+  expect(++o.f).toBe(3);
+  expect(++o.missing).toBeNaN();
 });