In ORCA, we donot process interrupts during planning stage, however
if there are elog/ereport (which further calls errfinish) statements to
print additional messages we prematurely exit out the planning stage
without cleaning up the memory pools leading to inconsistent memory pool
state. This results in crashes for the subsequent queries.

This commit fixes the issue by handling interrupts while
printing messages using elog/ereport in ORCA.
Signed-off-by: NEkta Khanna <ekhanna@pivotal.io>