Heap fill/compare; Std string experiments

tests/compiler/std/heap.ts

@@ -1,2 +1,21 @@
-let ptr: usize = Heap.allocate(10);
-Heap.dispose(ptr);
+const size: usize = 42;
+let ptr1: usize = Heap.allocate(size);
+let ptr2: usize = Heap.allocate(size);
+
+assert(ptr1 != ptr2);
+
+Heap.fill(ptr1, 0x12, size);
+
+let i: usize;
+for (i = 0; i < size; ++i)
+  assert(load<u8>(ptr1 + i) == 0x12);
+
+Heap.copy(ptr2, ptr1, size);
+
+for (i = 0; i < size; ++i)
+  assert(load<u8>(ptr2 + i) == 0x12);
+
+assert(Heap.compare(ptr1, ptr2, size) == 0);
+
+Heap.dispose(ptr1);
+Heap.dispose(ptr2);