Improve performance of dumpSequence().

This function dumps the sequence definitions.  It is called once
per sequence, and each such call executes a query to retrieve the
metadata for a single sequence.  This can cause pg_dump to take
significantly longer, especially when there are many sequences.

This commit improves the performance of this function by gathering
all the sequence metadata with a single query at the beginning of
pg_dump.  This information is stored in a sorted array that
dumpSequence() can bsearch() for what it needs.  This follows a
similar approach as commits d5e8930f50 and 2329cad1b9, which
introduced sorted arrays for role information and pg_class
information, respectively.  As with those commits, this patch will
cause pg_dump to use more memory, but that isn't expected to be too
egregious.

Note that before version 10, the sequence metadata was stored in
the sequence relation itself, which makes it difficult to gather
all the sequence metadata with a single query.  For those older
versions, we continue to use the preexisting query-per-sequence
approach.

Reviewed-by: Euler Taveira
Discussion: https://postgr.es/m/20240503025140.GA1227404%40nathanxps13

src/tools/pgindent/typedefs.list

@@ -2573,6 +2573,7 @@ SeqScanState
 SeqTable
 SeqTableData
 SeqType
+SequenceItem
 SerCommitSeqNo
 SerialControl
 SerialIOData