Bug#27753 enable mysql-test-run.pl to ignore tests based on wildcard

sub init_pattern {

  my ($from, $what)= @_;

  if ( $from =~ /[a-z0-9]/ ) {

  if ( $from =~ /^[a-z0-9]$/ ) {

    # Does not contain any regex, make the pattern match

    # beginning of string

    $from= "^$from";

  }

  else {

  # Check that pattern is a valid regex

  eval { "" =~/$from/; 1 } or

    mtr_error("Invalid regex '$from' passed to $what\nPerl says: $@");

  }

  return $from;

}