Changed avg aggregate functions to deal with system null. All aggregate functions now work properly for empty inputs, with and without local aggregation. Enabled tests.

git-svn-id: https://asterixdb.googlecode.com/svn/branches/asterix_fix_agg@530 eaa15691-b419-025a-1212-ee371bd00084
diff --git a/asterix-app/src/test/resources/runtimets/ignore.txt b/asterix-app/src/test/resources/runtimets/ignore.txt
index 43701fa..1ee67a3 100644
--- a/asterix-app/src/test/resources/runtimets/ignore.txt
+++ b/asterix-app/src/test/resources/runtimets/ignore.txt
@@ -36,5 +36,4 @@
 quantifiers/somesat_04.aql
 quantifiers/somesat_05.aql
 quantifiers/everysat_02.aql
-quantifiers/everysat_03.aql
-aggregate/avg_empty_02.aql
+quantifiers/everysat_03.aql
\ No newline at end of file