Windows, mtr - correctly determine CPU count, for --parallel=auto

mysql-test/mysql-test-run.pl

@@ -431,16 +431,21 @@ sub main {
   my $num_tests= @$tests;
   if ( $opt_parallel eq "auto" ) {
     # Try to find a suitable value for number of workers
-    my $sys_info= My::SysInfo->new();
-
-    $opt_parallel= $sys_info->num_cpus();
-    for my $limit (2000, 1500, 1000, 500){
-      $opt_parallel-- if ($sys_info->min_bogomips() < $limit);
+    if (IS_WINDOWS)
+    {
+      $opt_parallel= $ENV{NUMBER_OF_PROCESSORS} || 1;
+    }
+    else
+    {
+      my $sys_info= My::SysInfo->new();
+      $opt_parallel= $sys_info->num_cpus();
+      for my $limit (2000, 1500, 1000, 500){
+        $opt_parallel-- if ($sys_info->min_bogomips() < $limit);
+      }
     }
     my $max_par= $ENV{MTR_MAX_PARALLEL} || 8;
     $opt_parallel= $max_par if ($opt_parallel > $max_par);
     $opt_parallel= $num_tests if ($opt_parallel > $num_tests);
-    $opt_parallel= 1 if (IS_WINDOWS and $sys_info->isvm());
     $opt_parallel= 1 if ($opt_parallel < 1);
     mtr_report("Using parallel: $opt_parallel");
   }