Merge branch 'master' into fdw_core

diff --cc src/backend/commands/alter.c
Simple merge

diff --cc src/backend/parser/gram.y
Simple merge

diff --cc src/backend/tcop/utility.c
Simple merge

diff --cc src/bin/psql/tab-complete.c
Simple merge

diff --cc src/include/commands/defrem.h
Simple merge

diff --cc src/test/regress/expected/alter_table.out
Simple merge