Tighten up Windows CRLF conversion in our TAP test scripts.

The previous approach was to search-and-destroy all \r occurrences
no matter what.  That seems more likely to hide bugs than anything
else; indeed it seems to be hiding one now.  Fix things so that
we only transform \r\n to \n.

Side effects: must do this before, not after, chomp'ing if we're
going to chomp, else we'd fail to clean up a trailing \r\n.  Also,
remove safe_psql's redundant repetition of what psql already did;
else it might reduce \r\r\n to \n, which is exactly the scenario
I'm hoping to expose.

Perhaps this should be back-patched, but for now I'm content to
see what happens in HEAD.

Discussion: https://postgr.es/m/412ae8da-76bb-640f-039a-f3513499e53d@gmx.net

src/bin/pg_rewind/t/RewindTest.pm

@@ -112,7 +112,7 @@ sub check_query
 	}
 	else
 	{
-		$stdout =~ s/\r//g if $Config{osname} eq 'msys';
+		$stdout =~ s/\r\n/\n/g if $Config{osname} eq 'msys';
 		is($stdout, $expected_stdout, "$test_name: query result matches");
 	}
 	return;

src/test/perl/PostgresNode.pm

@@ -1324,7 +1324,6 @@ sub safe_psql
 		print "\n#### End standard error\n";
 	}
 
-	$stdout =~ s/\r//g if $TestLib::windows_os;
 	return $stdout;
 }
 
@@ -1515,14 +1514,14 @@ sub psql
 
 	if (defined $$stdout)
 	{
+		$$stdout =~ s/\r\n/\n/g if $TestLib::windows_os;
 		chomp $$stdout;
-		$$stdout =~ s/\r//g if $TestLib::windows_os;
 	}
 
 	if (defined $$stderr)
 	{
+		$$stderr =~ s/\r\n/\n/g if $TestLib::windows_os;
 		chomp $$stderr;
-		$$stderr =~ s/\r//g if $TestLib::windows_os;
 	}
 
 	# See http://perldoc.perl.org/perlvar.html#%24CHILD_ERROR
@@ -1652,8 +1651,8 @@ sub poll_query_until
 	{
 		my $result = IPC::Run::run $cmd, '>', \$stdout, '2>', \$stderr;
 
+		$stdout =~ s/\r\n/\n/g if $TestLib::windows_os;
 		chomp($stdout);
-		$stdout =~ s/\r//g if $TestLib::windows_os;
 
 		if ($stdout eq $expected)
 		{
@@ -1668,8 +1667,8 @@ sub poll_query_until
 
 	# The query result didn't change in 180 seconds. Give up. Print the
 	# output from the last attempt, hopefully that's useful for debugging.
+	$stderr =~ s/\r\n/\n/g if $TestLib::windows_os;
 	chomp($stderr);
-	$stderr =~ s/\r//g if $TestLib::windows_os;
 	diag qq(poll_query_until timed out executing this query:
 $query
 expecting this output:
@@ -2113,8 +2112,8 @@ sub pg_recvlogical_upto
 		}
 	};
 
-	$stdout =~ s/\r//g if $TestLib::windows_os;
-	$stderr =~ s/\r//g if $TestLib::windows_os;
+	$stdout =~ s/\r\n/\n/g if $TestLib::windows_os;
+	$stderr =~ s/\r\n/\n/g if $TestLib::windows_os;
 
 	if (wantarray)
 	{

src/test/perl/TestLib.pm

@@ -430,7 +430,7 @@ sub slurp_file
 		CloseHandle($fHandle)
 		  or die "could not close \"$filename\": $^E\n";
 	}
-	$contents =~ s/\r//g if $Config{osname} eq 'msys';
+	$contents =~ s/\r\n/\n/g if $Config{osname} eq 'msys';
 	return $contents;
 }