Assert the long soak's JS object growth from heap snapshots, and report compiled code, native memory and the used heap's slope apart

scripts/qa/heapSnapshotSizes.test.mjs

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+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { createHeapSnapshotSizes } from './heapSnapshotSizes.mjs';
+
+test('a streamed heap snapshot is sized per node type, however it is chunked', () => {
+  const snapshot = JSON.stringify({
+    snapshot: {
+      meta: {
+        node_fields: ['type', 'name', 'id', 'self_size', 'edge_count'],
+        node_types: [['hidden', 'object', 'code'], 'string', 'number'],
+      },
+      node_count: 4,
+    },
+    nodes: [1, 0, 1, 100, 0, 2, 0, 2, 4000, 0, 1, 0, 3, 23, 0, 0, 0, 4, 7, 0],
+    edges: [9, 9],
+    strings: ['x'],
+  });
+  for (const size of [snapshot.length, 7, 1]) {
+    const sizes = createHeapSnapshotSizes();
+    for (let i = 0; i < snapshot.length; i += size)
+      sizes.push(snapshot.slice(i, i + size));
+    assert.deepEqual(sizes.result(), { object: 123, code: 4000, hidden: 7 });
+  }
+});