remove most uses of Isolate::Current in arch specific files

src/arm/code-stubs-arm.h

Index: src/arm/code-stubs-arm.h
diff --git a/src/arm/code-stubs-arm.h b/src/arm/code-stubs-arm.h
index e7e7bfc00dbb0b530052073cff255c0b8b49a7d7..d05e9a1d840076e77af626c235ed5d0e2aa53cc6 100644
--- a/src/arm/code-stubs-arm.h
+++ b/src/arm/code-stubs-arm.h
@@ -68,7 +68,7 @@ class StoreBufferOverflowStub: public PlatformCodeStub {
 
   void Generate(MacroAssembler* masm);
 
-  virtual bool IsPregenerated() { return true; }
+  virtual bool IsPregenerated(Isolate* isolate) V8_OVERRIDE { return true; }
   static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);
   virtual bool SometimesSetsUpAFrame() { return false; }
 
@@ -232,7 +232,7 @@ class WriteInt32ToHeapNumberStub : public PlatformCodeStub {
         the_heap_number_(the_heap_number),
         scratch_(scratch) { }
 
-  bool IsPregenerated();
+  virtual bool IsPregenerated(Isolate* isolate) V8_OVERRIDE;
   static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);
 
  private:
@@ -305,7 +305,7 @@ class RecordWriteStub: public PlatformCodeStub {
     INCREMENTAL_COMPACTION
   };
 
-  virtual bool IsPregenerated();
+  virtual bool IsPregenerated(Isolate* isolate) V8_OVERRIDE;
   static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);
   virtual bool SometimesSetsUpAFrame() { return false; }