SERVER-12127 migrate js tests to jscore suite when not related to writes

Added relevant getLastError tests to jstests/gle/core

Author: renctan

jstests/error4.js

@@ -6,4 +6,29 @@ var coll = db.getCollection("gle_example");
 coll.drop();
 
 coll.insert({ hello : "world" });
-assert.eq( null, coll.getDB().getLastError() );
+assert.eq( null, coll.getDB().getLastError() );
+
+// Error on insert.
+coll.drop();
+coll.insert({ _id: 1 });
+coll.insert({ _id: 1 });
+var gle = db.getLastErrorObj();
+assert.neq(null, gle.err);
+
+// New requests should clear gle.
+coll.findOne();
+gle = db.getLastErrorObj();
+assert.eq(null, gle.err);
+
+// Error on upsert.
+coll.drop();
+coll.insert({ _id: 1 });
+coll.update({ y: 1 }, { _id: 1 }, true);
+gle = db.getLastErrorObj();
+assert.neq(null, gle.err);
+
+// Error on index creation.
+coll.ensureIndex({ x: 'invalid' });
+gle = db.getLastErrorObj();
+assert.neq(null, gle.err);
+