LibJS: Move tests to /Tests/LibJS

Author: https://github.com/gmta
Commit: https://github.com/LadybirdBrowser/ladybird/commit/e3faa9b5add
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/7572
Reviewed-by: https://github.com/trflynn89 ✅

Tests/LibJS/Runtime/builtins/SharedArrayBuffer/SharedArrayBuffer.js

@@ -0,0 +1,19 @@
+test("basic functionality", () => {
+    expect(SharedArrayBuffer).toHaveLength(1);
+    expect(SharedArrayBuffer.name).toBe("SharedArrayBuffer");
+    expect(SharedArrayBuffer.prototype.constructor).toBe(SharedArrayBuffer);
+    expect(new SharedArrayBuffer()).toBeInstanceOf(SharedArrayBuffer);
+    expect(typeof new SharedArrayBuffer()).toBe("object");
+});
+
+test("SharedArrayBuffer constructor must be invoked with 'new'", () => {
+    expect(() => {
+        SharedArrayBuffer();
+    }).toThrowWithMessage(TypeError, "SharedArrayBuffer constructor must be called with 'new'");
+});
+
+test("SharedArrayBuffer size limit", () => {
+    expect(() => {
+        new SharedArrayBuffer(2 ** 53);
+    }).toThrowWithMessage(RangeError, "Invalid shared array buffer length");
+});