Polymer tests require more heap.

sdk/bin/dartanalyzer_developer

 #!/bin/bash
 # Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # This file is used to execute the analyzer by running the jar file.
 # It is a simple wrapper enabling us to have simpler command lines in
 # the testing infrastructure.
 set -e
 
@@ skipping 36 matching lines @@
 else
   JAR_DIR="$CUR_DIR"/../../out/$DART_CONFIGURATION/dartanalyzer
 fi
 
 JAR_FILE="$JAR_DIR/dartanalyzer.jar"
 
 EXTRA_JVMARGS="-Xss2M "
 OS=`uname | tr "[A-Z]" "[a-z]"`
 if [ "$OS" == "darwin" ] ; then
   # Bump up the heap on Mac VMs, some of which default to 128M or less.
-  EXTRA_JVMARGS+=" -Xmx256M -client "
+  EXTRA_JVMARGS+=" -Xmx512M -client "
 else
   # On other architectures
   # -batch invocations will do better with a server vm
   # invocations for analyzing a single file do better with a client vm
   if [ $FOUND_BATCH -eq 0 ] ; then
     EXTRA_JVMARGS+=" -client "
   fi
 fi
 
 exec java $EXTRA_JVMARGS -jar $JAR_FILE --dart-sdk "$SDK_DIR" "$@"