pgsql: Add test for postgresql.conf.sample line syntax

Add test for postgresql.conf.sample line syntax

All GUCs in postgresql.conf.sample should be set to the default
value and be commented out.  This syntax was however not tested
for, making omissions easy to miss.  Add a test which check all
lines for syntax.

Author: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Andrew Dunstan <andrew@dunslane.net>
Discussion: https://postgr.es/m/19727040-3EE4-4719-AF4F-2548544113D7@yesql.se

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/446568c22207795da02e26b6b2956a61bd17e912

Modified Files
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src/test/modules/test_misc/t/003_check_guc.pl | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)