pgsql: Refactor reloption handling for index AMs in-core

Refactor reloption handling for index AMs in-core

This reworks the reloption parsing and build of a couple of index AMs by
creating new structures for each index AM's options.  This split was
already done for BRIN, GIN and GiST (which actually has a fillfactor
parameter), but not for hash, B-tree and SPGiST which relied on
StdRdOptions due to an overlap with the default option set.

This saves a couple of bytes for rd_options in each relcache entry with
indexes making use of relation options, and brings more consistency
between all index AMs.  While on it, add a couple of AssertMacro() calls
to make sure that utility macros to grab values of reloptions are used
with the expected index AM.

Author: Nikolay Shaplov
Reviewed-by: Amit Langote, Michael Paquier, Álvaro Herrera, Dent John
Discussion: https://postgr.es/m/4127670.gFlpRb6XCm@x200m

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/4cb658af70027c3544fb843d77b2e84028762747

Modified Files
--------------
src/backend/access/common/reloptions.c  |  4 +---
src/backend/access/hash/hashpage.c      |  2 +-
src/backend/access/hash/hashutil.c      |  9 ++++++++-
src/backend/access/nbtree/nbtree.c      |  4 ++--
src/backend/access/nbtree/nbtsort.c     |  4 ++--
src/backend/access/nbtree/nbtsplitloc.c |  2 +-
src/backend/access/nbtree/nbtutils.c    | 13 ++++++++++++-
src/backend/access/spgist/spgutils.c    | 13 ++++++++++---
src/include/access/brin.h               |  8 ++++++--
src/include/access/gin_private.h        |  9 +++++++--
src/include/access/hash.h               | 16 ++++++++++++++++
src/include/access/nbtree.h             | 18 ++++++++++++++++++
src/include/access/spgist.h             |  4 ----
src/include/access/spgist_private.h     | 22 ++++++++++++++++++++++
src/include/utils/rel.h                 |  3 +--
src/tools/pgindent/typedefs.list        |  3 +++
16 files changed, 110 insertions(+), 24 deletions(-)