Only if fork succeeded perform recv in isolation_testcase.py
Only if fork succeeded perform recv in isolation_testcase.py

Incase test fails on join, recv() is performed starting commit
2295c1fdcb85b029469b0783f6ff9d5d11c5864b. Due to this though later join hangs
forever, instead call recv() only if has_open is true means fork/blocking
happened to avoid the hang.

xinzweb/gpdb,adam8157/gpdb,jmcatamney/gpdb,edespino/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,Chibin/gpdb,adam8157/gpdb,adam8157/gpdb,lisakowen/gpdb,yuanzhao/gpdb,xinzweb/gpdb,edespino/gpdb,edespino/gpdb,xinzweb/gpdb,yuanzhao/gpdb,Chibin/gpdb,greenplum-db/gpdb,50wu/gpdb,lisakowen/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,lisakowen/gpdb,50wu/gpdb,greenplum-db/gpdb,edespino/gpdb,jmcatamney/gpdb,Chibin/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,50wu/gpdb,Chibin/gpdb,edespino/gpdb,Chibin/gpdb,xinzweb/gpdb,ashwinstar/gpdb,lisakowen/gpdb,lisakowen/gpdb,edespino/gpdb,yuanzhao/gpdb,xinzweb/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,Chibin/gpdb,yuanzhao/gpdb,lisakowen/gpdb,yuanzhao/gpdb,xinzweb/gpdb,edespino/gpdb,greenplum-db/gpdb,lisakowen/gpdb,greenplum-db/gpdb,adam8157/gpdb,xinzweb/gpdb,edespino/gpdb,greenplum-db/gpdb,lisakowen/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,adam8157/gpdb,edespino/gpdb,ashwinstar/gpdb,50wu/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,edespino/gpdb,ashwinstar/gpdb,50wu/gpdb,Chibin/gpdb,Chibin/gpdb,Chibin/gpdb,jmcatamney/gpdb,adam8157/gpdb,50wu/gpdb,greenplum-db/gpdb,xinzweb/gpdb,50wu/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,50wu/gpdb,ashwinstar/gpdb,adam8157/gpdb,adam8157/gpdb,Chibin/gpdb