[zone] Remove redundant size roundup in Zone

Change-Id: I2859b2f83a1b3a8f70f906f698a8531796b767af
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2436332Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70193}

src/zone/accounting-allocator.cc

@@ -108,7 +108,6 @@ void AccountingAllocator::ReturnSegment(Segment* segment,
   segment->ZapHeader();
   if (COMPRESS_ZONES_BOOL && supports_compression) {
     CHECK(FreePages(bounded_page_allocator_.get(), segment, segment_size));
-
   } else {
     free(segment);
   }

src/zone/zone.h

@@ -104,8 +104,7 @@ class V8_EXPORT_PRIVATE Zone final {
   // associated with the T type.
   template <typename T, typename... Args>
   T* New(Args&&... args) {
-    size_t size = RoundUp(sizeof(T), kAlignmentInBytes);
-    void* memory = Allocate<T>(size);
+    void* memory = Allocate<T>(sizeof(T));
     return new (memory) T(std::forward<Args>(args)...);
   }