Bug #54368 MTR does not recognize carriage return in --defaults-file

Remove any leftover trailing ^M from lines read in

mysql-test/lib/My/Config.pm

@@ -188,6 +188,8 @@ sub new {
 
   while (  my $line= <$F> ) {
     chomp($line);
+    # Remove any trailing CR from Windows edited files
+    $line=~ s/\cM$//;
 
     # [group]
     if ( $line =~ /^\[(.*)\]/ ) {