Initial ArrayBuffer implementation; Conditional allocation within constructors; Explicit constructor return values

tests/compiler/std/arraybuffer.ts

@@ -0,0 +1,39 @@
+import "allocator/arena";
+
+var buffer = new ArrayBuffer(8);
+
+assert(buffer.byteLength == 8);
+
+var sliced = buffer.slice();
+
+assert(sliced.byteLength == 8);
+assert(sliced != buffer);
+
+sliced = buffer.slice(1);
+
+assert(sliced.byteLength == 7);
+
+sliced = buffer.slice(-1);
+
+assert(sliced.byteLength == 1);
+
+sliced = buffer.slice(1, 3);
+
+assert(sliced.byteLength == 2);
+
+sliced = buffer.slice(1, -1);
+
+assert(sliced.byteLength == 6);
+
+sliced = buffer.slice(-3, -1);
+
+assert(sliced.byteLength == 2);
+
+sliced = buffer.slice(-4, 42);
+
+assert(sliced.byteLength == 4);
+
+sliced = buffer.slice(42);
+
+assert(sliced.byteLength == 0);
+assert(sliced != null);