pgsql: Remove variable "concurrent" from ReindexStmt

Remove variable "concurrent" from ReindexStmt

This node already handles multiple options using a bitmask, so having a
separate boolean flag is not necessary.  This simplifies the code a bit
with less arguments to give to the reindex routines, by replacing the
boolean with an equivalent bitmask value.

Reviewed-by: Julien Rouhaud
Discussion: https://postgr.es/m/20200902110326.GA14963@paquier.xyz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/844c05abc3f1c1703bf17cf44ab66351ed9711d2

Modified Files
--------------
src/backend/commands/indexcmds.c | 33 ++++++++++++++++++++-------------
src/backend/nodes/copyfuncs.c    |  1 -
src/backend/nodes/equalfuncs.c   |  1 -
src/backend/parser/gram.y        | 12 ++++++++----
src/backend/tcop/utility.c       |  8 ++++----
src/include/commands/defrem.h    |  6 +++---
src/include/nodes/parsenodes.h   |  2 +-
7 files changed, 36 insertions(+), 27 deletions(-)