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/add-values-to-primitive.js

@@ -1,6 +1,6 @@
 test("adding objects", () => {
-    expect([] + []).toBe("");
-    expect([] + {}).toBe("[object Object]");
-    expect({} + {}).toBe("[object Object][object Object]");
-    expect({} + []).toBe("[object Object]");
+  expect([] + []).toBe("");
+  expect([] + {}).toBe("[object Object]");
+  expect({} + {}).toBe("[object Object][object Object]");
+  expect({} + []).toBe("[object Object]");
 });