Update V8 to r4588

We're using WebKit r58033, as used by
http://src.chromium.org/svn/releases/5.0.387.0/DEPS
This requires http://v8.googlecode.com/svn/trunk@4465 but this version has a
crashing bug for ARM. Instead we use http://v8.googlecode.com/svn/trunk@4588,
which is used by http://src.chromium.org/svn/releases/6.0.399.0/DEPS

Note that a trivial bug fix was required in arm/codegen-arm.cc. This is guarded
with ANDROID. See http://code.google.com/p/v8/issues/detail?id=703

Change-Id: I459647a8286c4f8c7405f0c5581ecbf051a6f1e8
diff --git a/src/v8threads.cc b/src/v8threads.cc
index 80a7cd9..02292f6 100644
--- a/src/v8threads.cc
+++ b/src/v8threads.cc
@@ -331,6 +331,17 @@
 }
 
 
+void ThreadManager::IterateThreads(ThreadVisitor* v) {
+  for (ThreadState* state = ThreadState::FirstInUse();
+       state != NULL;
+       state = state->Next()) {
+    char* data = state->data();
+    data += HandleScopeImplementer::ArchiveSpacePerThread();
+    Top::IterateThread(v, data);
+  }
+}
+
+
 void ThreadManager::MarkCompactPrologue(bool is_compacting) {
   for (ThreadState* state = ThreadState::FirstInUse();
        state != NULL;