pgsql: Add Boolean node

Add Boolean node

Before, SQL-level boolean constants were represented by a string with
a cast, and internal Boolean values in DDL commands were usually
represented by Integer nodes. This takes the place of both of these
uses, making the intent clearer and having some amount of type safety.

Reviewed-by: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Discussion: https://www.postgresql.org/message-id/flat/8c1a2e37-c68d-703c-5a83-7a6077f4f997(at)enterprisedb(dot)com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/941460fcf731a32e6a90691508d5cfa3d1f8eeaf

Modified Files
--------------
contrib/postgres_fdw/postgres_fdw.c | 32 ++++----
src/backend/commands/define.c | 2 +
src/backend/commands/functioncmds.c | 14 ++--
src/backend/commands/sequence.c | 4 +-
src/backend/commands/tsearchcmds.c | 9 +++
src/backend/commands/user.c | 28 +++----
src/backend/nodes/copyfuncs.c | 16 ++++
src/backend/nodes/equalfuncs.c | 11 +++
src/backend/nodes/nodeFuncs.c | 1 +
src/backend/nodes/outfuncs.c | 8 ++
src/backend/nodes/read.c | 9 ++-
src/backend/nodes/value.c | 12 +++
src/backend/parser/gram.y | 99 +++++++++++++------------
src/backend/parser/parse_node.c | 8 ++
src/backend/replication/repl_gram.y | 14 ++--
src/include/nodes/nodes.h | 1 +
src/include/nodes/parsenodes.h | 1 +
src/include/nodes/value.h | 8 ++
src/test/isolation/expected/ri-trigger.out | 60 +++++++--------
src/test/regress/expected/create_function_3.out | 2 +-
20 files changed, 211 insertions(+), 128 deletions(-)