pgsql: Simplify restriction handling of two-phase commit for temporary

Simplify restriction handling of two-phase commit for temporary objects

There were two flags used to track the access to temporary tables and
to the temporary namespace of a session which are used to restrict
PREPARE TRANSACTION, however the first control flag is a concept
included in the second. This removes the flag for temporary table
tracking, keeping around only the one at namespace level.

Author: Michael Paquier
Reviewed-by: Álvaro Herrera
Discussion: https://postgr.es/m/20190118053126.GH1883@paquier.xyz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/c9b75c5838feeae73dbae00bce9d8f650b80ba38

Modified Files
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src/backend/access/common/relation.c | 4 ++--
src/backend/access/transam/xact.c | 19 ++++++-------------
src/backend/commands/lockcmds.c | 2 +-
src/backend/commands/tablecmds.c | 2 +-
src/include/access/xact.h | 12 +++---------
.../test_extensions/expected/test_extensions.out | 2 +-
src/test/regress/expected/temp.out | 22 +++++++++++-----------
7 files changed, 25 insertions(+), 38 deletions(-)