Move deopt_id and related helpers/definitions from Isolate to Thread

runtime/vm/intermediate_language_arm64.cc

Index: runtime/vm/intermediate_language_arm64.cc
diff --git a/runtime/vm/intermediate_language_arm64.cc b/runtime/vm/intermediate_language_arm64.cc
index 16ce91fdade8f47ceec5b52e669902628cdaa670..892a2967853107eeabbaa743c06dfc9d78e9a1f3 100644
--- a/runtime/vm/intermediate_language_arm64.cc
+++ b/runtime/vm/intermediate_language_arm64.cc
@@ -230,7 +230,7 @@ void ClosureCallInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   compiler->RecordSafepoint(locs());
   // Marks either the continuation point in unoptimized code or the
   // deoptimization point in optimized code, after call.
-  const intptr_t deopt_id_after = Isolate::ToDeoptAfter(deopt_id());
+  const intptr_t deopt_id_after = Thread::ToDeoptAfter(deopt_id());
   if (compiler->is_optimizing()) {
     compiler->AddDeoptIndexAtCall(deopt_id_after, token_pos());
   }