cppgc, heap: Don't eagerly allocate worklist segments

Bug: chromium:1056170
Change-Id: I75a6b5f52bfe8dd71abc086e5d1e060759ad7fc0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2391254
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69778}

BUILD.gn

@@ -4255,6 +4255,7 @@ v8_source_set("v8_cppgc_shared") {
   sources = [
     "src/heap/base/stack.cc",
     "src/heap/base/stack.h",
+    "src/heap/base/worklist.cc",
     "src/heap/base/worklist.h",
   ]
 

src/heap/base/worklist.cc

+// Copyright 2020 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/heap/base/worklist.h"
+
+namespace heap {
+namespace base {
+namespace internal {
+SegmentBase SegmentBase::kSentinelSegment(0);
+}  // namespace internal
+}  // namespace base
+}  // namespace heap