bug: base_url is missing.

Why missing next line in theme in 4.7.0 beta 6 and RC1?

<base href="http://test.local:8080" />

By this not show some pictures in my own theme page.
Example not displayed picture for page http://test.local:8080/node/9:
http://test.local:8080/node/9/themes/mcptc/images/title_ibridge.gif

if missing base tag in output html, some pathes is become relative current url.
I adding some code in common.inc:

/**
 * Retrieve output to be displayed in the head tag of the HTML page.
 */
function drupal_get_html_head() {
global $base_url; //sk patch by adding
  $output = "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\" />\n";
$output .= "<base href=\"$base_url\" />\n"; //sk patch by adding
  $output .= theme('stylesheet_import', base_path() .'misc/drupal.css');
  return $output . drupal_set_html_head();
}

Comment:
http://test.local:8080 - this is my test local webserver url
Tested bug:
Opera 8.5, 9.0, IE 6