Resolve some disagreements between SIMARM and XARM on offsets used in compiled code.

runtime/vm/isolate.cc

Index: runtime/vm/isolate.cc
diff --git a/runtime/vm/isolate.cc b/runtime/vm/isolate.cc
index 41b223fef84de6de97cd6c4150a65fe68a3fc47e..69d7ab1e05cd229cff9e3bff6343c16213b0a5cc 100644
--- a/runtime/vm/isolate.cc
+++ b/runtime/vm/isolate.cc
@@ -655,9 +655,15 @@ void BaseIsolate::AssertCurrentThreadIsMutator() const {
   object##_handle_(NULL),
 
 Isolate::Isolate(const Dart_IsolateFlags& api_flags)
-  :   vm_tag_(0),
+  :   stack_limit_(0),
       store_buffer_(new StoreBuffer()),
       heap_(NULL),
+      vm_tag_(0),
+      user_tag_(0),
+      current_tag_(UserTag::null()),
+      default_tag_(UserTag::null()),
+      class_table_(),
+      single_step_(false),
       thread_registry_(new ThreadRegistry()),
       message_notify_callback_(NULL),
       name_(NULL),
@@ -675,7 +681,6 @@ Isolate::Isolate(const Dart_IsolateFlags& api_flags)
       library_tag_handler_(NULL),
       api_state_(NULL),
       debugger_(NULL),
-      single_step_(false),
       resume_request_(false),
       last_resume_timestamp_(OS::GetCurrentTimeMillis()),
       has_compiled_(false),
@@ -685,7 +690,6 @@ Isolate::Isolate(const Dart_IsolateFlags& api_flags)
       timer_list_(),
       deopt_id_(0),
       mutex_(new Mutex()),
-      stack_limit_(0),
       saved_stack_limit_(0),
       stack_base_(0),
       stack_overflow_flags_(0),
@@ -708,8 +712,6 @@ Isolate::Isolate(const Dart_IsolateFlags& api_flags)
       trace_buffer_(NULL),
       profiler_data_(NULL),
       tag_table_(GrowableObjectArray::null()),
-      current_tag_(UserTag::null()),
-      default_tag_(UserTag::null()),
       collected_closures_(GrowableObjectArray::null()),
       deoptimized_code_array_(GrowableObjectArray::null()),
       pending_service_extension_calls_(GrowableObjectArray::null()),