LibJS: Reorganize tests into subfolders

Author: https://github.com/mattco98
Commit: https://github.com/SerenityOS/serenity/commit/4c48c9d69d3
Pull-request: https://github.com/SerenityOS/serenity/pull/2681
Reviewed-by: https://github.com/linusg

Libraries/LibJS/Tests/builtins/Object/Object.preventExtensions.js

@@ -0,0 +1,54 @@
+load("test-common.js");
+
+try {
+    assert(Object.preventExtensions() === undefined);
+    assert(Object.preventExtensions(undefined) === undefined);
+    assert(Object.preventExtensions(null) === null);
+    assert(Object.preventExtensions(true) === true);
+    assert(Object.preventExtensions(6) === 6);
+    assert(Object.preventExtensions("test") === "test");
+
+    let s = Symbol();
+    assert(Object.preventExtensions(s) === s);
+
+    let o = { foo: "foo" };
+    assert(o.foo === "foo");
+    o.bar = "bar";
+    assert(o.bar === "bar");
+
+    assert(Object.preventExtensions(o) === o);
+    assert(o.foo === "foo");
+    assert(o.bar === "bar");
+
+    o.baz = "baz";
+    assert(o.baz === undefined);
+
+    assertThrowsError(() => {
+        Object.defineProperty(o, "baz", { value: "baz" });
+    }, {
+        error: TypeError,
+        message: "Cannot define property baz on non-extensible object",
+    });
+
+    assert(o.baz === undefined);
+
+    assertThrowsError(() => {
+        "use strict";
+        o.baz = "baz";
+    }, {
+        error: TypeError,
+        message: "Cannot define property baz on non-extensible object",
+    });
+
+    assertThrowsError(() => {
+        "use strict";
+        Object.defineProperty(o, "baz", { value: "baz" });
+    }, {
+        error: TypeError,
+        message: "Cannot define property baz on non-extensible object",
+    });
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}