pgsql: Correctly handle test durations of more than 2147s in pg_test_ti

Correctly handle test durations of more than 2147s in pg_test_timing.

Previously the computation of the total test duration, measured in
microseconds, accidentally overflowed due to accidentally using signed
32bit arithmetic.  As the only consequence is that pg_test_timing
invocations with such, overly large, durations never finished the
practical consequences of this bug are minor.

Pointed out by Coverity.

Backpatch to 9.2 where pg_test_timing was added.

Branch
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REL9_3_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/a68b8aec71c8ab0aefe9888041172d1482c7d276

Modified Files
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contrib/pg_test_timing/pg_test_timing.c |    2 +-
1 file changed, 1 insertion(+), 1 deletion(-)