Increase the heap growth rate as it decreases compile-time by as much as 10%.

dart/utils/compiler/build_helper.dart

Index: dart/utils/compiler/build_helper.dart
diff --git a/dart/utils/compiler/build_helper.dart b/dart/utils/compiler/build_helper.dart
index fa2ec0c3687c8bafabf2d75841764578c66e5482..77f11cb370c58df32d0e943db4aa55d3e6114f5a 100644
--- a/dart/utils/compiler/build_helper.dart
+++ b/dart/utils/compiler/build_helper.dart
@@ -94,12 +94,12 @@ List<String> buildScript(String name,
   // Tell the VM to grow the heap more aggressively. This should only
   // be necessary temporarily until the VM is better at detecting how
   // applications use memory.
-  // TODO(ahe): Remove this option.
-  options = ' --heap_growth_rate=32$options';
+  // TODO(ahe): Remove this option (http://dartbug.com/6495).
+  options = ' --heap_growth_rate=512$options';
 
   // Tell the VM to don't bother inlining methods. So far it isn't
   // paying off but the VM team is working on fixing that.
-  // TODO(ahe): Remove this option.
+  // TODO(ahe): Remove this option (http://dartbug.com/6495).
   options = ' --no_use_inlining$options';
 
   return [