Revert "try fix: move notify under mutex"

This reverts commit ac8acbb0be02b0bd2a6d33208b93a2327185d805.
diff --git a/kotlin-native/runtime/src/gc/cms/cpp/ParallelMark.cpp b/kotlin-native/runtime/src/gc/cms/cpp/ParallelMark.cpp
index 0c387cd..d90b610 100644
--- a/kotlin-native/runtime/src/gc/cms/cpp/ParallelMark.cpp
+++ b/kotlin-native/runtime/src/gc/cms/cpp/ParallelMark.cpp
@@ -31,9 +31,8 @@
         std::unique_lock lock(mutex_);
         GCLogDebug(epoch_.load(), "Phase #%d begins", phase); // FIXME
         phase_.store(phase, std::memory_order_release);
-        // FIXME move out?
-        cond_.notify_all();
     }
+    cond_.notify_all();
 }
 
 void gc::mark::MarkPacer::wait(gc::mark::MarkPacer::Phase phase) {