pgsql: Minor fixups of test_bitmapset.c

Minor fixups of test_bitmapset.c

The macro's comment had become outdated from a prior version and there's
now no longer a need for the do/while loop (or my misplaced semi-colon).

Author: David Rowley <dgrowleyml@gmail.com>
Discussion: https://postgr.es/m/CAApHDvr+P454SP_LDvB=bViPAbDQhV1Jmg5M55GEKz0d3z25NA@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/3a661580685964dd2ca192306a202934f268fc5c

Modified Files
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src/test/modules/test_bitmapset/test_bitmapset.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)