Revert "Temporary workaround to make qp_dml_joins deterministic"

A proper fix to ensure that a QE writer signals QE readers before
aborting a transaction is made in PR #6089.  The temporary workaround
is no longer necessary.

This reverts commit b6dd73a4.
Co-authored-by: NAsim R P <apraveen@pivotal.io>

src/test/regress/expected/qp_dml_joins.out

@@ -3125,14 +3125,6 @@ SELECT SUM(b) FROM dml_heap_pt_r;
 (1 row)
 
 ALTER TABLE dml_heap_pt_r ADD DEFAULT partition def;
--- Temporary workaround to make the error reported by the following
--- update statement deterministic.  Without the savepoint, a QE reader
--- may continue performing its part of the plan even after its writer
--- has finished aborting the transaction.  This would lead to
--- occasional "relation not found for OID ..." errors because the
--- default partition would have been dropped as part of writer's abort
--- processing.
-SAVEPOINT sp1;
 UPDATE dml_heap_pt_r SET a = DEFAULT, b = DEFAULT;
 ERROR:  cross-partition or multi-update to a row  (seg1 10.152.10.75:25433 pid=28939)
 SELECT SUM(a) FROM dml_heap_pt_r;
@@ -3286,14 +3278,6 @@ SELECT * FROM dml_heap_pt_r WHERE a = 1;
 (1 row)
 
 ALTER TABLE dml_heap_pt_r ADD DEFAULT partition def;
--- Temporary workaround to make the error reported by the following
--- update statement deterministic.  Without the savepoint, a QE reader
--- may continue performing its part of the plan even after its writer
--- has finished aborting the transaction.  This would lead to
--- occasional "relation not found for OID ..." errors because the
--- default partition would have been dropped as part of writer's abort
--- processing.
-SAVEPOINT sp1;
 UPDATE dml_heap_pt_r SET a = dml_heap_pt_s.a + 10 ,b = NULL FROM dml_heap_pt_s WHERE dml_heap_pt_r.a + 2= dml_heap_pt_s.b;
 ERROR:  cross-partition or multi-update to a row  (seg2 10.152.10.75:25434 pid=14697)
 SELECT * FROM dml_heap_pt_r WHERE a = 11 ORDER BY 1,2;

src/test/regress/expected/qp_dml_joins_optimizer.out

@@ -3129,14 +3129,6 @@ SELECT SUM(b) FROM dml_heap_pt_r;
 (1 row)
 
 ALTER TABLE dml_heap_pt_r ADD DEFAULT partition def;
--- Temporary workaround to make the error reported by the following
--- update statement deterministic.  Without the savepoint, a QE reader
--- may continue performing its part of the plan even after its writer
--- has finished aborting the transaction.  This would lead to
--- occasional "relation not found for OID ..." errors because the
--- default partition would have been dropped as part of writer's abort
--- processing.
-SAVEPOINT sp1;
 UPDATE dml_heap_pt_r SET a = DEFAULT, b = DEFAULT;
 SELECT SUM(a) FROM dml_heap_pt_r;
  sum 
@@ -3297,14 +3289,6 @@ SELECT * FROM dml_heap_pt_r WHERE a = 1;
 (1 row)
 
 ALTER TABLE dml_heap_pt_r ADD DEFAULT partition def;
--- Temporary workaround to make the error reported by the following
--- update statement deterministic.  Without the savepoint, a QE reader
--- may continue performing its part of the plan even after its writer
--- has finished aborting the transaction.  This would lead to
--- occasional "relation not found for OID ..." errors because the
--- default partition would have been dropped as part of writer's abort
--- processing.
-SAVEPOINT sp1;
 UPDATE dml_heap_pt_r SET a = dml_heap_pt_s.a + 10 ,b = NULL FROM dml_heap_pt_s WHERE dml_heap_pt_r.a + 2= dml_heap_pt_s.b;
 ERROR:  cross-partition or multi-update to a row
 SELECT * FROM dml_heap_pt_r WHERE a = 11 ORDER BY 1,2;

src/test/regress/sql/qp_dml_joins.sql

@@ -1352,16 +1352,6 @@ begin;
 SELECT SUM(a) FROM dml_heap_pt_r;
 SELECT SUM(b) FROM dml_heap_pt_r;
 ALTER TABLE dml_heap_pt_r ADD DEFAULT partition def;
-
--- Temporary workaround to make the error reported by the following
--- update statement deterministic.  Without the savepoint, a QE reader
--- may continue performing its part of the plan even after its writer
--- has finished aborting the transaction.  This would lead to
--- occasional "relation not found for OID ..." errors because the
--- default partition would have been dropped as part of writer's abort
--- processing.
-SAVEPOINT sp1;
-
 UPDATE dml_heap_pt_r SET a = DEFAULT, b = DEFAULT;
 SELECT SUM(a) FROM dml_heap_pt_r;
 SELECT SUM(b) FROM dml_heap_pt_r;
@@ -1427,16 +1417,6 @@ SELECT COUNT(*) FROM dml_heap_pt_r WHERE b is NULL;
 SELECT dml_heap_pt_s.a + 10 FROM dml_heap_pt_r,dml_heap_pt_s WHERE dml_heap_pt_r.a = dml_heap_pt_s.a ORDER BY 1 LIMIT 1;
 SELECT * FROM dml_heap_pt_r WHERE a = 1;
 ALTER TABLE dml_heap_pt_r ADD DEFAULT partition def;
-
--- Temporary workaround to make the error reported by the following
--- update statement deterministic.  Without the savepoint, a QE reader
--- may continue performing its part of the plan even after its writer
--- has finished aborting the transaction.  This would lead to
--- occasional "relation not found for OID ..." errors because the
--- default partition would have been dropped as part of writer's abort
--- processing.
-SAVEPOINT sp1;
-
 UPDATE dml_heap_pt_r SET a = dml_heap_pt_s.a + 10 ,b = NULL FROM dml_heap_pt_s WHERE dml_heap_pt_r.a + 2= dml_heap_pt_s.b;
 SELECT * FROM dml_heap_pt_r WHERE a = 11 ORDER BY 1,2;
 SELECT COUNT(*) FROM dml_heap_pt_r WHERE b is NULL;