LibJS: Reorganize tests into subfolders

Author: https://github.com/mattco98
Commit: 4c48c9d69d
Pull-request: https://github.com/SerenityOS/serenity/pull/2681
Reviewed-by: https://github.com/linusg

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

@@ -0,0 +1,23 @@
+load("test-common.js");
+
+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);
+}