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

src/arm/regexp-macro-assembler-arm.cc

Index: src/arm/regexp-macro-assembler-arm.cc
diff --git a/src/arm/regexp-macro-assembler-arm.cc b/src/arm/regexp-macro-assembler-arm.cc
index 2a81facacfaa5ba2b8e2ad6b7a4679a561243a17..a26aa9e39f3427d8085c924a77701d84d85497cb 100644
--- a/src/arm/regexp-macro-assembler-arm.cc
+++ b/src/arm/regexp-macro-assembler-arm.cc
@@ -872,7 +872,7 @@ Handle<HeapObject> RegExpMacroAssemblerARM::GetCode(Handle<String> source) {
   masm_->GetCode(&code_desc);
   Handle<Code> code = isolate()->factory()->NewCode(
       code_desc, Code::ComputeFlags(Code::REGEXP), masm_->CodeObject());
-  PROFILE(Isolate::Current(), RegExpCodeCreateEvent(*code, *source));
+  PROFILE(masm_->isolate(), RegExpCodeCreateEvent(*code, *source));
   return Handle<HeapObject>::cast(code);
 }
 
@@ -1097,7 +1097,6 @@ int RegExpMacroAssemblerARM::CheckStackGuardState(Address* return_address,
                                                   Code* re_code,
                                                   Address re_frame) {
   Isolate* isolate = frame_entry<Isolate*>(re_frame, kIsolate);
-  ASSERT(isolate == Isolate::Current());
   if (isolate->stack_guard()->IsStackOverflow()) {
     isolate->StackOverflow();
     return EXCEPTION;