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

src/arm/debug-arm.cc

Index: src/arm/debug-arm.cc
diff --git a/src/arm/debug-arm.cc b/src/arm/debug-arm.cc
index 108435f0a9f9b795d67827ecc5a69b9247127b2e..efd11069b323a5813afe72e9d423a2b9e588f99b 100644
--- a/src/arm/debug-arm.cc
+++ b/src/arm/debug-arm.cc
@@ -55,7 +55,8 @@ void BreakLocationIterator::SetDebugBreakAtReturn() {
   CodePatcher patcher(rinfo()->pc(), Assembler::kJSReturnSequenceInstructions);
   patcher.masm()->ldr(v8::internal::ip, MemOperand(v8::internal::pc, 0));
   patcher.masm()->blx(v8::internal::ip);
-  patcher.Emit(Isolate::Current()->debug()->debug_break_return()->entry());
+  patcher.Emit(
+      debug_info_->GetIsolate()->debug()->debug_break_return()->entry());
   patcher.masm()->bkpt(0);
 }
 
@@ -95,7 +96,8 @@ void BreakLocationIterator::SetDebugBreakAtSlot() {
   CodePatcher patcher(rinfo()->pc(), Assembler::kDebugBreakSlotInstructions);
   patcher.masm()->ldr(v8::internal::ip, MemOperand(v8::internal::pc, 0));
   patcher.masm()->blx(v8::internal::ip);
-  patcher.Emit(Isolate::Current()->debug()->debug_break_slot()->entry());
+  patcher.Emit(
+      debug_info_->GetIsolate()->debug()->debug_break_slot()->entry());
 }