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

test/unittests/BUILD.gn

 # Copyright 2016 The V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("../../gni/v8.gni")
 
 v8_executable("unittests") {
   testonly = true
 
   sources = [
@@ skipping 125 matching lines @@
     "wasm/function-body-decoder-unittest.cc",
     "wasm/leb-helper-unittest.cc",
     "wasm/loop-assignment-analysis-unittest.cc",
     "wasm/module-decoder-unittest.cc",
     "wasm/switch-logic-unittest.cc",
     "wasm/wasm-macro-gen-unittest.cc",
     "wasm/wasm-module-builder-unittest.cc",
     "wasm/wasm-opcodes-unittest.cc",
     "zone/segmentpool-unittest.cc",
     "zone/zone-chunk-list-unittest.cc",
+    "zone/zone-unittest.cc",
   ]
 
   if (v8_current_cpu == "arm") {
     sources += [ "compiler/arm/instruction-selector-arm-unittest.cc" ]
   } else if (v8_current_cpu == "arm64") {
     sources += [ "compiler/arm64/instruction-selector-arm64-unittest.cc" ]
   } else if (v8_current_cpu == "x86") {
     sources += [ "compiler/ia32/instruction-selector-ia32-unittest.cc" ]
   } else if (v8_current_cpu == "mips" || v8_current_cpu == "mipsel") {
     sources += [ "compiler/mips/instruction-selector-mips-unittest.cc" ]
@@ skipping 31 matching lines @@
     deps += [ "//third_party/icu" ]
   }
 
   if (is_win) {
     # This warning is benignly triggered by the U16 and U32 macros in
     # bytecode-utils.h.
     # C4309: 'static_cast': truncation of constant value
     cflags = [ "/wd4309" ]
   }
 }