LibJS: Add six typed arrays (signed and unsigned 8/16/32-bit)

This patch adds six of the standard type arrays and tries to share as
much code as possible:

- Uint8Array
- Uint16Array
- Uint32Array
- Int8Array
- Int16Array
- Int32Array

Libraries/LibJS/Tests/builtins/TypedArray/typed-array-basic.js

@@ -0,0 +1,86 @@
+test("basic Uint8Array", () => {
+    var a = new Uint8Array(1);
+    expect(typeof a).toBe("object");
+    expect(a instanceof Uint8Array).toBe(true);
+    expect(a.length).toBe(1);
+    a[0] = 1;
+    expect(a[0]).toBe(1);
+    a[0] -= 2;
+    expect(a[0]).toBe(0xff);
+    ++a[0];
+    expect(a[0]).toBe(0);
+});
+
+test("basic Uint16Array", () => {
+    var a = new Uint16Array(1);
+    expect(typeof a).toBe("object");
+    expect(a instanceof Uint16Array).toBe(true);
+    expect(a.length).toBe(1);
+    a[0] = 1;
+    expect(a[0]).toBe(1);
+    a[0] -= 2;
+    expect(a[0]).toBe(0xffff);
+    ++a[0];
+    expect(a[0]).toBe(0);
+});
+
+test("basic Uint32Array", () => {
+    var a = new Uint32Array(1);
+    expect(typeof a).toBe("object");
+    expect(a instanceof Uint32Array).toBe(true);
+    expect(a.length).toBe(1);
+    a[0] = 1;
+    expect(a[0]).toBe(1);
+    a[0] -= 2;
+    expect(a[0]).toBe(0xffffffff);
+    ++a[0];
+    expect(a[0]).toBe(0);
+});
+
+test("basic Int8Array", () => {
+    var a = new Int8Array(1);
+    expect(typeof a).toBe("object");
+    expect(a instanceof Int8Array).toBe(true);
+    expect(a.length).toBe(1);
+    a[0] = 1;
+    expect(a[0]).toBe(1);
+    a[0] -= 2;
+    expect(a[0]).toBe(-1);
+    ++a[0];
+    expect(a[0]).toBe(0);
+    a[0] = 127;
+    a[0]++;
+    expect(a[0]).toBe(-128);
+});
+
+test("basic Int16Array", () => {
+    var a = new Int16Array(1);
+    expect(typeof a).toBe("object");
+    expect(a instanceof Int16Array).toBe(true);
+    expect(a.length).toBe(1);
+    a[0] = 1;
+    expect(a[0]).toBe(1);
+    a[0] -= 2;
+    expect(a[0]).toBe(-1);
+    ++a[0];
+    expect(a[0]).toBe(0);
+    a[0] = 32767;
+    a[0]++;
+    expect(a[0]).toBe(-32768);
+});
+
+test("basic Int32Array", () => {
+    var a = new Int32Array(1);
+    expect(typeof a).toBe("object");
+    expect(a instanceof Int32Array).toBe(true);
+    expect(a.length).toBe(1);
+    a[0] = 1;
+    expect(a[0]).toBe(1);
+    a[0] -= 2;
+    expect(a[0]).toBe(-1);
+    ++a[0];
+    expect(a[0]).toBe(0);
+    a[0] = 0x7fffffff;
+    a[0]++;
+    expect(a[0]).toBe(-0x80000000);
+});