pgsql: Revert indexed and enlargable binary heap implementation.

Revert indexed and enlargable binary heap implementation.

This reverts commit b840508644 and bcb14f4abc. These commits were made
for commit 5bec1d6bc5 (Improve eviction algorithm in ReorderBuffer
using max-heap for many subtransactions). However, per discussion,
commit efb8acc0d0 replaced binary heap + index with pairing heap, and
made these commits unnecessary.

Reported-by: Jeff Davis
Discussion: https://postgr.es/m/12747c15811d94efcc5cda72d6b35c80d7bf3443.camel%40j-davis.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/810f64a01567610af7b92b0de930f16f3e20064e

Modified Files
--------------
src/backend/executor/nodeGatherMerge.c | 1 -
src/backend/executor/nodeMergeAppend.c | 2 +-
src/backend/postmaster/pgarch.c | 3 +-
src/backend/replication/logical/reorderbuffer.c | 1 -
src/backend/storage/buffer/bufmgr.c | 1 -
src/bin/pg_dump/pg_backup_archiver.c | 1 -
src/bin/pg_dump/pg_dump_sort.c | 2 +-
src/common/binaryheap.c | 245 ++++--------------------
src/include/lib/binaryheap.h | 40 +---
src/tools/pgindent/typedefs.list | 1 -
10 files changed, 38 insertions(+), 259 deletions(-)