Ensure we align zone memory at 8 byte boundaries on all platforms

src/zone/zone.h

Index: src/zone/zone.h
diff --git a/src/zone/zone.h b/src/zone/zone.h
index 4e3b96eb206e8ff1a247130600ea3ac5e341e3c8..dbc1dadadd6d99d778af7a53a6b52904a2d1ae2b 100644
--- a/src/zone/zone.h
+++ b/src/zone/zone.h
@@ -63,16 +63,8 @@ class V8_EXPORT_PRIVATE Zone final {
   AccountingAllocator* allocator() const { return allocator_; }
 
  private:
-// All pointers returned from New() have this alignment.  In addition, if the
-// object being allocated has a size that is divisible by 8 then its alignment
-// will be 8. ASan requires 8-byte alignment. MIPS also requires 8-byte
-// alignment.
-#if defined(V8_USE_ADDRESS_SANITIZER) || defined(V8_TARGET_ARCH_MIPS)
-  static const size_t kAlignment = 8;
-  STATIC_ASSERT(kPointerSize <= 8);
-#else
-  static const size_t kAlignment = kPointerSize;
-#endif
+  // All pointers returned from New() are 8-byte aligned.
+  static const size_t kAlignmentInBytes = 8;
 
   // Never allocate segments smaller than this size in bytes.
   static const size_t kMinimumSegmentSize = 8 * KB;