add tests

svn path=/trunk/mcs/; revision=124207

mcs/class/System.Core/System.Core_test.dll.sources

@@ -2,6 +2,7 @@ System/TimeZoneInfoTest.cs
 System/TimeZoneInfo.AdjustmentRuleTest.cs
 System/TimeZoneInfo.TransitionTimeTest.cs
 System.Collections.Generic/HashSetTest.cs
+System.Linq/EnumerableFixture.cs
 System.Linq/EnumerableTest.cs
 System.Linq/EnumerableMoreTest.cs
 System.Linq/EnumerableAsQueryableTest.cs