Update V8 to version 4.1.0.21

This is a cherry-pick of all commits up to and including the
4.1.0.21 cherry-pick in Chromium.

Original commit message:

Version 4.1.0.21 (cherry-pick)

Merged 206e9136bde0f2b5ae8cb77afbb1e7833e5bd412

Unlink pages from the space page list after evacuation.

BUG=430201
LOG=N
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/953813002

Cr-Commit-Position: refs/branch-heads/4.1@{#22}
Cr-Branched-From: 2e08d2a7aa9d65d269d8c57aba82eb38a8cb0a18-refs/heads/candidates@{#25353}

---

FPIIM-449

Change-Id: I8c23c7bbb70772b4858fe8a47b64fa97ee0d1f8c
diff --git a/src/base/atomicops.h b/src/base/atomicops.h
index eba172f..675e43f 100644
--- a/src/base/atomicops.h
+++ b/src/base/atomicops.h
@@ -25,7 +25,7 @@
 #ifndef V8_BASE_ATOMICOPS_H_
 #define V8_BASE_ATOMICOPS_H_
 
-#include "include/v8stdint.h"
+#include <stdint.h>
 #include "src/base/build_config.h"
 
 #if defined(_WIN32) && defined(V8_HOST_ARCH_64_BIT)
@@ -42,15 +42,17 @@
 
 typedef char Atomic8;
 typedef int32_t Atomic32;
-#ifdef V8_HOST_ARCH_64_BIT
+#if defined(__native_client__)
+typedef int64_t Atomic64;
+#elif defined(V8_HOST_ARCH_64_BIT)
 // We need to be able to go between Atomic64 and AtomicWord implicitly.  This
 // means Atomic64 and AtomicWord should be the same type on 64-bit.
 #if defined(__ILP32__)
 typedef int64_t Atomic64;
 #else
 typedef intptr_t Atomic64;
-#endif
-#endif
+#endif  // defined(V8_HOST_ARCH_64_BIT)
+#endif  // defined(__native_client__)
 
 // Use AtomicWord for a machine-sized pointer.  It will use the Atomic32 or
 // Atomic64 routines below, depending on your architecture.
@@ -140,6 +142,8 @@
 #include "src/base/atomicops_internals_x86_msvc.h"
 #elif defined(__APPLE__)
 #include "src/base/atomicops_internals_mac.h"
+#elif defined(__native_client__)
+#include "src/base/atomicops_internals_portable.h"
 #elif defined(__GNUC__) && V8_HOST_ARCH_ARM64
 #include "src/base/atomicops_internals_arm64_gcc.h"
 #elif defined(__GNUC__) && V8_HOST_ARCH_ARM