pgsql: Check for stack overrun in standard_ProcessUtility().

Check for stack overrun in standard_ProcessUtility().

ProcessUtility can recurse, and indeed can be driven to infinite
recursion, so it ought to have a check_stack_depth() call.  This
covers the reported bug (portal trying to execute itself) and a bunch
of other cases that could perhaps arise somewhere.

Per bug #15428 from Malthe Borch.  Back-patch to all supported branches.

Discussion: https://postgr.es/m/15428-b3c2915ec470b033@postgresql.org

Branch
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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/9d4212afa100ca3a03bb5d12e1caf6c205457117

Modified Files
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src/backend/tcop/utility.c | 3 +++
1 file changed, 3 insertions(+)