pgsql: Add EXPLAIN (IO) instrumentation for TidRangeScan

Add EXPLAIN (IO) instrumentation for TidRangeScan

Adds support for EXPLAIN (IO) instrumentation for TidRange scans. This
requires adding shared instrumentation for parallel scans, using the
separate DSM approach introduced by dd78e69cfc33.

Author: Tomas Vondra <tomas(at)vondra(dot)me>
Reviewed-by: Melanie Plageman <melanieplageman(at)gmail(dot)com>
Reviewed-by: Lukas Fittl <lukas(at)fittl(dot)com>
Reviewed-by: Andres Freund <andres(at)anarazel(dot)de>
Discussion: https://postgr.es/m/flat/a177a6dd-240b-455a-8f25-aca0b1c08c6e%40vondra.me

Branch
------
master

Details
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https://git.postgresql.org/pg/commitdiff/e157fe6f76e0be4f05a725b3099cf53949a2c2af

Modified Files
--------------
src/backend/commands/explain.c | 25 ++++++
src/backend/executor/execParallel.c | 12 +++
src/backend/executor/nodeTidrangescan.c | 133 ++++++++++++++++++++++++++++++--
src/include/executor/instrument_node.h | 18 +++++
src/include/executor/nodeTidrangescan.h | 9 +++
src/include/nodes/execnodes.h | 1 +
src/tools/pgindent/typedefs.list | 2 +
7 files changed, 192 insertions(+), 8 deletions(-)