Don't try to test files named with a trailing dot on Windows
Don't try to test files named with a trailing dot on Windows

The pg_verify_checksums test tries to create files with corrupt data
named "123." and "123_." But on Windows a file name with a trailing dot
is the same as a file without the trailing dot. In the first case this
will create a file with a "valid" name, which causes the test to fail in
an unexpected way, and in the secongd case this will be redandant as the
test already creates a file named "123_".

Bug discovered by buildfarm animal bowerbird.

50wu/gpdb,xinzweb/gpdb,greenplum-db/gpdb,50wu/gpdb,greenplum-db/gpdb,lisakowen/gpdb,lisakowen/gpdb,xinzweb/gpdb,xinzweb/gpdb,50wu/gpdb,lisakowen/gpdb,greenplum-db/gpdb,50wu/gpdb,adam8157/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,xinzweb/gpdb,adam8157/gpdb,greenplum-db/gpdb,adam8157/gpdb,adam8157/gpdb,50wu/gpdb,lisakowen/gpdb,50wu/gpdb,lisakowen/gpdb,adam8157/gpdb,lisakowen/gpdb,xinzweb/gpdb,xinzweb/gpdb,xinzweb/gpdb,50wu/gpdb,adam8157/gpdb,lisakowen/gpdb,greenplum-db/gpdb,50wu/gpdb,adam8157/gpdb,adam8157/gpdb,xinzweb/gpdb,lisakowen/gpdb