Do 2 GCs on LowMemoryNotification instead of 7.

src/mark-compact.cc

Index: src/mark-compact.cc
===================================================================
--- src/mark-compact.cc	(revision 12520)
+++ src/mark-compact.cc	(working copy)
@@ -1248,7 +1248,8 @@
     }
 
     // Age this shared function info.
-    if (shared_info->code_age() < kCodeAgeThreshold) {
+    if (!heap->flush_eagerly() &&
+        shared_info->code_age() < kCodeAgeThreshold) {
       shared_info->set_code_age(shared_info->code_age() + 1);
       return false;
     }
@@ -1325,7 +1326,8 @@
       }
 
       // Check if we should flush now.
-      if (value == ((heap->sweep_generation() - kRegExpCodeThreshold) & 0xff)) {
+      if (heap->flush_eagerly() ||
+          value == ((heap->sweep_generation() - kRegExpCodeThreshold) & 0xff)) {
         re->SetDataAtUnchecked(JSRegExp::code_index(is_ascii),
                                Smi::FromInt(JSRegExp::kUninitializedValue),
                                heap);