Reclassify heapsnapshot and nsJSInspector as not part of devtools

This resolves Issue #316

dom/heapsnapshot/tests/unit/test_HeapAnalyses_computeDominatorTree_02.js

@@ -0,0 +1,23 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test the HeapAnalyses{Client,Worker} "computeDominatorTree" request with bad
+// file paths.
+
+function run_test() {
+  run_next_test();
+}
+
+add_task(function* () {
+  const client = new HeapAnalysesClient();
+
+  let threw = false;
+  try {
+    yield client.computeDominatorTree("/etc/passwd");
+  } catch (_) {
+    threw = true;
+  }
+  ok(threw, "should throw when given a bad path");
+
+  client.destroy();
+});