[heap] Fix address space leak in Unmapper

src/heap/spaces-inl.h

Index: src/heap/spaces-inl.h
diff --git a/src/heap/spaces-inl.h b/src/heap/spaces-inl.h
index 2079a80a0b00f0130aea154d0e873f7d5dbfcce1..73f138f2b2555ea2024a61e8b9e1586e6fb09e6e 100644
--- a/src/heap/spaces-inl.h
+++ b/src/heap/spaces-inl.h
@@ -15,6 +15,22 @@
 namespace v8 {
 namespace internal {
 
+template <MemoryAllocator::AllocationMode alloc_mode, typename SpaceType>
+Page* MemoryAllocator::AllocatePage(size_t size, SpaceType* owner,
+                                    Executability executable) {
+  MemoryChunk* chunk = nullptr;
+  if (alloc_mode == kPooled) {
+    DCHECK_EQ(size, static_cast<size_t>(MemoryChunk::kAllocatableMemory));
+    DCHECK_EQ(executable, NOT_EXECUTABLE);
+    chunk = AllocatePagePooled(owner);
+  }
+  if (chunk == nullptr) {
+    chunk = AllocateChunk(size, size, executable, owner);
+  }
+  if (chunk == nullptr) return nullptr;
+  return Page::Initialize(isolate_->heap(), chunk, executable, owner);
+}
+
 template <class PAGE_TYPE>
 PageIteratorImpl<PAGE_TYPE>& PageIteratorImpl<PAGE_TYPE>::operator++() {
   p_ = p_->next_page();