LibJS: Convert most builtin tests to new system

Libraries/LibJS/Tests/builtins/Error/Error.js

@@ -1,33 +1,18 @@
-load("test-common.js");
+test("basic functionality", () => {
+    expect(Error).toHaveLength(1);
+    expect(Error.name).toBe("Error");
+});
 
-try {
-    assert(Error.length === 1);
-    assert(Error.name === "Error");
-    assert(Error.prototype.length === undefined);
+test("name", () => {
+    [Error(), Error(undefined), Error("test"), Error(42), Error(null)].forEach(error => {
+        expect(error.name).toBe("Error");
+    });
+});
 
-    var e;
-
-    e = Error();
-    assert(e.name === "Error");
-    assert(e.message === "");
-
-    e = Error(undefined);
-    assert(e.name === "Error");
-    assert(e.message === "");
-
-    e = Error("test");
-    assert(e.name === "Error");
-    assert(e.message === "test");
-
-    e = Error(42);
-    assert(e.name === "Error");
-    assert(e.message === "42");
-
-    e = Error(null);
-    assert(e.name === "Error");
-    assert(e.message === "null");
-
-    console.log("PASS");
-} catch (e) {
-    console.log("FAIL: " + e);
-}
+test("message", () => {
+    expect(Error().message).toBe("");
+    expect(Error(undefined).message).toBe("");
+    expect(Error("test").message).toBe("test");
+    expect(Error(42).message).toBe("42");
+    expect(Error(null).message).toBe("null");
+});

Libraries/LibJS/Tests/builtins/Error/Error.prototype.name.js

@@ -1,14 +1,10 @@
-load("test-common.js");
-
-try {
+test("basic functionality", () => {
+    expect(Error.prototype).not.toHaveProperty("length");
+    
     var changedInstance = new Error("");
-    changedInstance.name = 'NewCustomError';
-    assert(changedInstance.name === "NewCustomError");
+    changedInstance.name = "NewCustomError";
+    expect(changedInstance.name).toBe("NewCustomError");
 
     var normalInstance = new Error("");
-    assert(normalInstance.name === "Error");
-
-    console.log("PASS");
-} catch (e) {
-    console.log("FAIL: " + e.message);
-}
+    expect(normalInstance.name).toBe("Error");
+});

Libraries/LibJS/Tests/builtins/Error/Error.prototype.toString.js

@@ -1,13 +1,7 @@
-load("test-common.js");
-
-try {
-    assert(Error().toString() === "Error");
-    assert(Error(undefined).toString() === "Error");
-    assert(Error(null).toString() === "Error: null");
-    assert(Error("test").toString() === "Error: test");
-    assert(Error(42).toString() === "Error: 42");
-
-    console.log("PASS");
-} catch (e) {
-    console.log("FAIL: " + e);
-}
+test("basic functionality", () => {
+    expect(Error().toString()).toBe("Error");
+    expect(Error(undefined).toString()).toBe("Error");
+    expect(Error(null).toString()).toBe("Error: null");
+    expect(Error("test").toString()).toBe("Error: test");
+    expect(Error(42).toString()).toBe("Error: 42");
+});