cppgc: Check success of permissions update in FreePages

Bug: chromium:1249752
Change-Id: I18dee16c13f504f6669395f0ce4a753177aec9f5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3165059
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Auto-Submit: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76880}

src/heap/cppgc/caged-heap.cc

@@ -61,7 +61,7 @@ class CppgcBoundedPageAllocator final : public v8::base::BoundedPageAllocator {
     // contents. To mitigate this problem, CppgcBoundedPageAllocator clears all
     // pages before they are freed. This also includes protected guard pages, so
     // CppgcBoundedPageAllocator needs to update permissions before clearing.
-    SetPermissions(address, size, Permission::kReadWrite);
+    CHECK(SetPermissions(address, size, Permission::kReadWrite));
     memset(address, 0, size);
     return v8::base::BoundedPageAllocator::FreePages(address, size);
   }