pgsql: Update time zone data files to tzdata release 2018c.

Update time zone data files to tzdata release 2018c.

DST law changes in Brazil, Sao Tome and Principe. Historical corrections
for Bolivia, Japan, and South Sudan. The "US/Pacific-New" zone has been
removed (it was only a link to America/Los_Angeles anyway).

Branch
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REL9_3_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/e5e2cc6f8c1d257991804021d64270e544a81297

Modified Files
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src/timezone/data/tzdata.zi | 22 +++++++++++++---------
src/timezone/known_abbrevs.txt | 1 -
src/timezone/tznames/Africa.txt | 3 +--
3 files changed, 14 insertions(+), 12 deletions(-)