[ticket/12232] Remove excessive calls to sizeof() in assign_block_vars() method

The size of the template block array is calculated within a foreach loop
iterating through the array, which is unnecessary. It only needs to be done
once. In a block of 1000 rows, this results in
500,500 calls to sizeof() in this location. With this change, that's reduced to
1000.

PHPBB3-12232
[ticket/12232] Fix a similar excessive pattern in the method.

PHPBB3-12232
Merge pull request #2065 from prototech/ticket/12232

[ticket/12232] Remove excessive calls to sizeof() in assign_block_vars() method.
[ticket/12126] Fixed position of alert box in IE

PHPBB3-12126
[ticket/12126] Changed .phpbb_alert "max-width: 640px" to "width: 620px"

PHPBB3-12126
[ticket/11645] Rename .MODs tab in ACP to Extensions

http://tracker.phpbb.com/browse/PHPBB3-11645

PHPBB3-11645
[ticket/9255] Added max-height and overflow-x to cp-mini in cp.css

PHPBB3-9255
[ticket/9255] Changed overflow-x to overflow-y

PHPBB3-9255
[ticket/12126] left:0 and right: 0; admin.css --> width: auto

PHPBB3-12126
[ticket/12126] deleted left:0 and right:0 in responsive.css .phpbb_alert

PHPBB3-12126
Merge remote-tracking branch 'Crizz0/ticket/12126' into develop

* Crizz0/ticket/12126:
  [ticket/12126] deleted left:0 and right:0 in responsive.css .phpbb_alert
  [ticket/12126] left:0 and right: 0; admin.css --> width: auto
  [ticket/12126] Changed .phpbb_alert "max-width: 640px" to "width: 620px"
  [ticket/12126] Fixed position of alert box in IE
Merge remote-tracking branch 'Crizz0/ticket/9255' into develop

* Crizz0/ticket/9255:
  [ticket/9255] Changed overflow-x to overflow-y
  [ticket/9255] Added max-height and overflow-x to cp-mini in cp.css
Merge remote-tracking branch 'vsephpbb/ticket/11645' into develop

* vsephpbb/ticket/11645:
  [ticket/11645] Rename .MODs tab in ACP to Extensions