Fix places in TestLib.pm in need of adaptation to the output of Msys perl

Contrary to the output of native perl, Msys perl generates outputs with
CRLFs characters.  There are already places in the TAP code where CRLFs
(\r\n) are automatically converted to LF (\n) on Msys, but we missed a
couple of places when running commands and using their output for
comparison, that would lead to failures.

This problem has been found thanks to the test added in 5adb067 using
TestLib::command_checks_all(), but after a closer look more code paths
were missing a filter.

This is backpatched all the way down to prevent any surprises if a new
test is introduced in stable branches.

Reviewed-by: Andrew Dunstan, Álvaro Herrera
Discussion: https://postgr.es/m/1252480.1631829409@sss.pgh.pa.us
Backpatch-through: 9.6

src/test/perl/TestLib.pm

@@ -434,6 +434,7 @@ sub run_command
 	my ($cmd) = @_;
 	my ($stdout, $stderr);
 	my $result = IPC::Run::run $cmd, '>', \$stdout, '2>', \$stderr;
+	foreach ($stderr, $stdout) { s/\r\n/\n/g if $Config{osname} eq 'msys'; }
 	chomp($stdout);
 	chomp($stderr);
 	return ($stdout, $stderr);
@@ -878,6 +879,7 @@ sub command_like
 	my $result = IPC::Run::run $cmd, '>', \$stdout, '2>', \$stderr;
 	ok($result, "$test_name: exit code 0");
 	is($stderr, '', "$test_name: no stderr");
+	$stdout =~ s/\r\n/\n/g if $Config{osname} eq 'msys';
 	like($stdout, $expected_stdout, "$test_name: matches");
 	return;
 }
@@ -930,6 +932,7 @@ sub command_fails_like
 	print("# Running: " . join(" ", @{$cmd}) . "\n");
 	my $result = IPC::Run::run $cmd, '>', \$stdout, '2>', \$stderr;
 	ok(!$result, "$test_name: exit code not 0");
+	$stderr =~ s/\r\n/\n/g if $Config{osname} eq 'msys';
 	like($stderr, $expected_stderr, "$test_name: matches");
 	return;
 }
@@ -974,6 +977,8 @@ sub command_checks_all
 	  if $ret & 127;
 	$ret = $ret >> 8;
 
+	foreach ($stderr, $stdout) { s/\r\n/\n/g if $Config{osname} eq 'msys'; }
+
 	# check status
 	ok($ret == $expected_ret,
 		"$test_name status (got $ret vs expected $expected_ret)");