Fix Debian compilation error

runtime/vm/compiler.cc

Index: runtime/vm/compiler.cc
diff --git a/runtime/vm/compiler.cc b/runtime/vm/compiler.cc
index 50e2e554e72b10ce0e1e23953c8a87a71cf267bc..7685b3cc9ca637489d83babb67de9a6072ab4593 100644
--- a/runtime/vm/compiler.cc
+++ b/runtime/vm/compiler.cc
@@ -1565,14 +1565,13 @@ RawObject* Compiler::EvaluateStaticInitializer(const Field& field) {
   // evaluating the initializer value.
   ASSERT(field.StaticValue() == Object::transition_sentinel().raw());
   LongJumpScope jump;
-  Thread* thread = Thread::Current();
   if (setjmp(*jump.Set()) == 0) {
+    Thread* const thread = Thread::Current();
     NoOOBMessageScope no_msg_scope(thread);
     NoReloadScope no_reload_scope(thread->isolate(), thread);
     // Under lazy compilation initializer has not yet been created, so create
     // it now, but don't bother remembering it because it won't be used again.
     ASSERT(!field.HasPrecompiledInitializer());
-    Thread* const thread = Thread::Current();
     Function& initializer = Function::Handle(thread->zone());
     {
       NOT_IN_PRODUCT(