This patch removes code support for PG9.6 and PG10. In addition to
removing PG96 and PG10 macros the following changes are done:
remove HAVE_INT64_TIMESTAMP since this is always true on PG10+
remove PG_VERSION_SUPPORTS_MULTINODE
Due to the changes of the default view behaviour of continuous
aggregates we need a new testsuite for the update tests for 1.7.0
This patch also changes the update test for 9.6 and 10 to run on
cron and 11 and 12 on pull request.