pgsql: Convert datetime input functions to use "soft" error reporting.

Convert datetime input functions to use "soft" error reporting.

This patch converts the input functions for date, time, timetz,
timestamp, timestamptz, and interval to the new soft-error style.
There's some related stuff in formatting.c that remains to be
cleaned up, but that seems like a separable project.

Discussion: https://postgr.es/m/3bbbb0df-7382-bf87-9737-340ba096e034@postgrespro.ru

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/c60488b4748b4316f1c92d62457671046e5c8994

Modified Files
--------------
src/backend/utils/adt/date.c | 31 ++++++----
src/backend/utils/adt/datetime.c | 22 +++++---
src/backend/utils/adt/formatting.c | 21 ++++---
src/backend/utils/adt/timestamp.c | 94 ++++++++++++++++---------------
src/include/utils/datetime.h | 12 ++--
src/test/regress/expected/date.out | 31 ++++++++++
src/test/regress/expected/interval.out | 31 ++++++++++
src/test/regress/expected/time.out | 31 ++++++++++
src/test/regress/expected/timestamp.out | 31 ++++++++++
src/test/regress/expected/timestamptz.out | 31 ++++++++++
src/test/regress/expected/timetz.out | 31 ++++++++++
src/test/regress/sql/date.sql | 7 +++
src/test/regress/sql/interval.sql | 7 +++
src/test/regress/sql/time.sql | 7 +++
src/test/regress/sql/timestamp.sql | 7 +++
src/test/regress/sql/timestamptz.sql | 7 +++
src/test/regress/sql/timetz.sql | 7 +++
17 files changed, 328 insertions(+), 80 deletions(-)