LibJS: Convert most builtin tests to new system

Author: https://github.com/mattco98
Commit: 3f97d75778
Pull-request: https://github.com/SerenityOS/serenity/pull/2689
Reviewed-by: https://github.com/linusg

Libraries/LibJS/Tests/builtins/String/String.js

@@ -1,23 +1,9 @@
-load("test-common.js");
+test("constructor properties", () => {
+    expect(String).toHaveLength(1);
+    expect(String.name).toBe("String");
+});
 
-try {
-    assert(String.length === 1);
-    assert(String.name === "String");
-    assert(String.prototype.length === 0);
-
-    assert(typeof String() === "string");
-    assert(typeof new String() === "object");
-
-    assert(String() === "");
-    assert(new String().valueOf() === "");
-    assert(String("foo") === "foo");
-    assert(new String("foo").valueOf() === "foo");
-    assert(String(123) === "123");
-    assert(new String(123).valueOf() === "123");
-    assert(String(123) === "123");
-    assert(new String(123).valueOf() === "123");
-
-    console.log("PASS");
-} catch (e) {
-    console.log("FAIL: " + e);
-}
+test("typeof", () => {
+    expect(typeof String()).toBe("string");
+    expect(typeof new String()).toBe("object");
+});