Fix builds

runtime/vm/simulator_arm64.cc

Index: runtime/vm/simulator_arm64.cc
diff --git a/runtime/vm/simulator_arm64.cc b/runtime/vm/simulator_arm64.cc
index cdbf5ce4128aae196e7dcf15a177c87ef1dbb49a..cf25e24096c3ab29052eefd47e3e6a2ddac0af3c 100644
--- a/runtime/vm/simulator_arm64.cc
+++ b/runtime/vm/simulator_arm64.cc
@@ -3520,7 +3520,6 @@ void Simulator::Longjmp(uword pc,
   // The C++ caller has not cleaned up the stack memory of C++ frames.
   // Prepare for unwinding frames by destroying all the stack resources
   // in the previous C++ frames.
-  Isolate* isolate = thread->isolate();
   StackResource::Unwind(thread);
 
   // Unwind the C++ stack and continue simulation in the target frame.
@@ -3531,7 +3530,7 @@ void Simulator::Longjmp(uword pc,
   // Set the tag.
   thread->set_vm_tag(VMTag::kDartTagId);
   // Clear top exit frame.
-  isolate->set_top_exit_frame_info(0);
+  thread->set_top_exit_frame_info(0);
 
   ASSERT(raw_exception != Object::null());
   set_register(NULL, kExceptionObjectReg, bit_cast<int64_t>(raw_exception));