Flush Memoize cache when non-key parameters change, take 2

It's possible that a subplan below a Memoize node contains a parameter
from above the Memoize node.  If this parameter changes then cache entries
may become out-dated due to the new parameter value.

Previously Memoize was mistakenly not aware of this.  We fix this here by
flushing the cache whenever a parameter that's not part of the cache
key changes.

Bug: #17213
Reported by: Elvis Pranskevichus
Author: David Rowley
Discussion: https://postgr.es/m/17213-988ed34b225a2862@postgresql.org
Backpatch-through: 14, where Memoize was added

src/backend/nodes/bitmapset.c

@@ -540,6 +540,8 @@ bms_overlap_list(const Bitmapset *a, const List *b)
 
 /*
  * bms_nonempty_difference - do sets have a nonempty difference?
+ *
+ * i.e., are any members set in 'a' that are not also set in 'b'.
  */
 bool
 bms_nonempty_difference(const Bitmapset *a, const Bitmapset *b)

src/backend/nodes/copyfuncs.c

@@ -973,6 +973,7 @@ _copyMemoize(const Memoize *from)
 	COPY_SCALAR_FIELD(singlerow);
 	COPY_SCALAR_FIELD(binary_mode);
 	COPY_SCALAR_FIELD(est_entries);
+	COPY_BITMAPSET_FIELD(keyparamids);
 
 	return newnode;
 }

src/backend/nodes/outfuncs.c

@@ -868,6 +868,7 @@ _outMemoize(StringInfo str, const Memoize *node)
 	WRITE_BOOL_FIELD(singlerow);
 	WRITE_BOOL_FIELD(binary_mode);
 	WRITE_UINT_FIELD(est_entries);
+	WRITE_BITMAPSET_FIELD(keyparamids);
 }
 
 static void

src/backend/nodes/readfuncs.c

@@ -2232,6 +2232,7 @@ _readMemoize(void)
 	READ_BOOL_FIELD(singlerow);
 	READ_BOOL_FIELD(binary_mode);
 	READ_UINT_FIELD(est_entries);
+	READ_BITMAPSET_FIELD(keyparamids);
 
 	READ_DONE();
 }