Fix typos.

Test: art/test/testrunner/testrunner.py
Change-Id: I5f5e052c940650a3adb3a8717b84260e6b306500
diff --git a/runtime/runtime.h b/runtime/runtime.h
index 7ab9be5..c7f650e 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -325,7 +325,7 @@
   // instead.
   void VisitImageRoots(RootVisitor* visitor) REQUIRES_SHARED(Locks::mutator_lock_);
 
-  // Visit all of the roots we can do safely do concurrently.
+  // Visit all of the roots we can safely visit concurrently.
   void VisitConcurrentRoots(RootVisitor* visitor,
                             VisitRootFlags flags = kVisitRootFlagAllRoots)
       REQUIRES(!Locks::classlinker_classes_lock_, !Locks::trace_lock_)