Backport fix for finding executables from 5.0

mysql-test/lib/mtr_misc.pl:
  On windows the exe does not need to be executable for it to be found

mysql-test/lib/mtr_misc.pl

@@ -82,7 +82,14 @@ sub mtr_path_exists (@) {
 sub mtr_script_exists (@) {
   foreach my $path ( @_ )
   {
-    return $path if -x $path;
+    if($::glob_win32)
+    {
+      return $path if -f $path;
+    }
+    else
+    {
+      return $path if -x $path;
+    }
   }
   if ( @_ == 1 )
   {
@@ -99,7 +106,14 @@ sub mtr_exe_exists (@) {
   map {$_.= ".exe"} @path if $::glob_win32;
   foreach my $path ( @path )
   {
-    return $path if -x $path;
+    if($::glob_win32)
+    {
+      return $path if -f $path;
+    }
+    else
+    {
+      return $path if -x $path;
+    }
   }
   if ( @path == 1 )
   {