Restart idle GC round on context disposal.

src/heap/gc-idle-time-handler.cc

Index: src/heap/gc-idle-time-handler.cc
diff --git a/src/heap/gc-idle-time-handler.cc b/src/heap/gc-idle-time-handler.cc
index a3383b9c0c0dcde34864a7fbbafef853d24d5d55..4d7414c2f75ba62b530939024da2e8c478e7b350 100644
--- a/src/heap/gc-idle-time-handler.cc
+++ b/src/heap/gc-idle-time-handler.cc
@@ -217,10 +217,10 @@ GCIdleTimeAction GCIdleTimeHandler::NothingOrDone() {
 // that this currently may trigger a full garbage collection.
 GCIdleTimeAction GCIdleTimeHandler::Compute(double idle_time_in_ms,
                                             HeapState heap_state) {
+  if (heap_state.contexts_disposed > 0) {
+    StartIdleRound();
+  }
   if (static_cast<int>(idle_time_in_ms) <= 0) {
-    if (heap_state.contexts_disposed > 0) {
-      StartIdleRound();
-    }
     if (heap_state.incremental_marking_stopped) {
       if (ShouldDoContextDisposalMarkCompact(
               heap_state.contexts_disposed,