diff --git a/runtime/tests/vm/vm.status b/runtime/tests/vm/vm.status
index 251fd9a..0f8ce61 100644
--- a/runtime/tests/vm/vm.status
+++ b/runtime/tests/vm/vm.status
@@ -144,9 +144,6 @@
 cc/PrintJSON: Crash
 cc/Service_TokenStream: Crash
 
-[ ($compiler == dartk || $compiler == dartkb) && $runtime == vm ]
-dart/appjit_cha_deopt_test: Pass, RuntimeError # Issue 34627
-
 # Enabling of dartk for sim{arm,arm64,dbc64} revelaed these test failures, which
 # are to be triaged.  Isolate tests are skipped on purpose due to the usage of
 # batch mode.
diff --git a/runtime/vm/class_finalizer.cc b/runtime/vm/class_finalizer.cc
index 09fa482..847a4a1 100644
--- a/runtime/vm/class_finalizer.cc
+++ b/runtime/vm/class_finalizer.cc
@@ -1760,6 +1760,11 @@
   Thread* T = Thread::Current();
   Zone* Z = T->zone();
   Isolate* I = T->isolate();
+
+  // Prevent background compiler from adding deferred classes or canonicalizing
+  // new types while classes are being sorted and type hashes are modified.
+  BackgroundCompiler::Stop(I);
+
   ClassTable* table = I->class_table();
   intptr_t num_cids = table->NumCids();
   intptr_t* old_to_new_cid = new intptr_t[num_cids];