pgsql: Change contrib/pg_test_fsync to control tests in terms of second

Change contrib/pg_test_fsync to control tests in terms of seconds per
test, rather than a number of test cycles. Changes -o/cycles option to
-s/seconds.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/0a8396e35e2e230da7539372b32968c0d959fba8

Modified Files
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contrib/pg_test_fsync/pg_test_fsync.c | 108 ++++++++++++++++++--------------
doc/src/sgml/pgtestfsync.sgml | 8 +-
2 files changed, 65 insertions(+), 51 deletions(-)