MDEV-26972 MTR worker aborts after server restart failure

restore the old behavior where without a debugger mtr does not
wait for mysqld to start. It was broken in feacc0aa

mysql-test/mysql-test-run.pl

@@ -5072,6 +5072,7 @@ sub mysqld_start ($$) {
   # Differs from "generic" MYSQLD_CMD by including all command line
   # options from *.opt and *.combination files.
   $ENV{'MYSQLD_LAST_CMD'}= "$exe  @$args";
+  my $oldexe= $exe;
 
   My::Debugger::setup_args(\$args, \$exe, $mysqld->name());
   $ENV{'VALGRIND_TEST'}= $opt_valgrind = int(($exe || '') eq 'valgrind');
@@ -5127,8 +5128,9 @@ sub mysqld_start ($$) {
   $mysqld->{'started_opts'}= $extra_opts;
 
   my $expect_file= "$opt_vardir/tmp/".$mysqld->name().".expect";
-  return sleep_until_file_created($mysqld->value('pid-file'), $expect_file,
-           $opt_start_timeout, $mysqld->{'proc'}, $warn_seconds);
+  return $oldexe eq $exe ||
+         sleep_until_file_created($mysqld->value('pid-file'), $expect_file,
+                     $opt_start_timeout, $mysqld->{'proc'}, $warn_seconds);
 }