heap: Enable lazy commits for Fuchsia

Bug: v8:12050
Change-Id: I599338eba458e177327870699b6ea8a423e144c2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3211577
Commit-Queue: Wez <wez@chromium.org>
Auto-Submit: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77530}

src/base/platform/platform-fuchsia.cc

@@ -156,10 +156,7 @@ bool OS::DecommitPages(void* address, size_t size) {
 }
 
 // static
-bool OS::HasLazyCommits() {
-  // TODO(scottmg): Port, https://crbug.com/731217.
-  return false;
-}
+bool OS::HasLazyCommits() { return true; }
 
 std::vector<OS::SharedLibraryAddress> OS::GetSharedLibraryAddresses() {
   UNREACHABLE();  // TODO(scottmg): Port, https://crbug.com/731217.