pgsql: Change qr/foo$/m to qr/foo\n/m, for Perl 5.8.8.

Change qr/foo$/m to qr/foo\n/m, for Perl 5.8.8.

In each case, absence of a trailing newline would itself constitute a
PostgreSQL bug. Therefore, this slightly enhances the changed tests.
This works around a bug that last appeared in Perl 5.8.8, fixing
src/test/modules/test_pg_dump when run against that version. Commit
e7293e3271bf618eeb2d4779a15fc516a69fe463 worked around the bug, but the
subsequent addition of test_pg_dump introduced affected code. As that
commit had shown, slight increases in pattern complexity can suppress
the bug. This commit edits qr/foo$/m patterns too complex to encounter
the bug today, for style consistency and robustness against unrelated
pattern changes. Back-patch to 9.6, where test_pg_dump was introduced.

As of this writing, a fresh MSYS installation includes an affected Perl
5.8.8. The Perl 5.8.8 in Red Hat Enterprise Linux 5.11 carries a patch
that renders it unaffected, but the Perl 5.8.5 of Red Hat Enterprise
Linux 4.4 is affected.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/650b96707672599e290c982dd63e3a896dbbaba6

Modified Files
--------------
src/bin/pg_basebackup/t/010_pg_basebackup.pl | 8 ++---
src/test/modules/test_pg_dump/t/001_base.pl | 48 ++++++++++++++--------------
src/test/perl/README | 4 +++
src/tools/msvc/Project.pm | 2 +-
4 files changed, 32 insertions(+), 30 deletions(-)