[NO ISSUE][COMP] Support OFFSET without LIMIT

- user model changes: yes
- storage format changes: no
- interface changes: no

Details:
- Add support for a standalone OFFSET clause
  (without LIMIT clause)
- Add testcases and update documentation

Change-Id: I1c8b968fcc8beaa1028b8370610ff490e391d6f9
Reviewed-on: https://asterix-gerrit.ics.uci.edu/c/asterixdb/+/8963
Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Dmitry Lychagin <dmitry.lychagin@couchbase.com>
Reviewed-by: Ali Alsuliman <ali.al.solaiman@gmail.com>
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml b/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml
index 7f002ee..be711d3 100644
--- a/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml
@@ -13949,6 +13949,11 @@
       </compilation-unit>
     </test-case>
     <test-case FilePath="limit">
+      <compilation-unit name="offset_without_limit">
+        <output-dir compare="Text">offset_without_limit</output-dir>
+      </compilation-unit>
+    </test-case>
+    <test-case FilePath="limit">
       <compilation-unit name="push-limit-to-external-scan">
         <output-dir compare="Text">push-limit-to-external-scan</output-dir>
       </compilation-unit>