pgsql: Add more TAP test coverage for pg_dump.

Add more TAP test coverage for pg_dump.

Add a test case to cover pg_dump with --compress=none.  This
brings the coverage of compress_none.c up from about 64% to 90%,
in particular covering the new code added in a previous patch.

Include compression of toc.dat in manually-compressed test cases.
We would have found the bug fixed in commit a239c4a0c much sooner
if we'd done this.  As far as I can tell, this doesn't reduce test
coverage at all, since there are other tests of directory format
that still use an uncompressed toc.dat.

Widen the wide row used to verify correct (de) compression.
Commit 1a05c1d25 advises us (not without reason) to ensure that
this test case fully fills DEFAULT_IO_BUFFER_SIZE, so that loops
within the compression logic will iterate completely.  To follow
that advice with the proposed DEFAULT_IO_BUFFER_SIZE of 128K,
we need something close to this.  This does indeed increase the
reported code coverage by a few lines.

While here, fix a glitch that I noticed in testing: the
$glob_patterns tests were incapable of failing, because glob()
will return 'foo' as 'foo' whether there is a matching file or
not.  (Indeed, the stanza just above that one relies on that.)

In my testing, this patch adds approximately as much runtime
as was saved by the previous patch, so that it's about a wash
compared to the old code.  However, we get better test coverage.

Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/3515357.1760128017@sss.pgh.pa.us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/20ec9958921af9698e88d6f006c49a4d9d28f210

Modified Files
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src/bin/pg_dump/t/002_pg_dump.pl          |  8 +++-
src/bin/pg_dump/t/006_pg_dump_compress.pl | 66 +++++++++++++++++++++----------
2 files changed, 52 insertions(+), 22 deletions(-)