Missing plugin description in 3.0 (encoding issue?)

[aleksanderkuczek]

Case: WP Super Cache

old entry: ​https://wordpress.org/plugins/wp-super-cache/
new entry: ​https://wordpress.org/plugins-wp/wp-super-cache/

In the new entry from imported data has no description, FAQ and some of the authors missing.

@obenland suggests it might be en encoding issue

[dd32]

Upon looking at this, the following is failing on the contents of the trunk readme in Readme\Parser:

$contents = preg_split( '!\R!u', $contents );

If I remove the utf8 modifier it processes. I assume this is caused by invalid UTF8 in the readme.
The UTF8 specifier is there as it was matching \r or \n as part of a UTF8 multi-byte character previously.

[Otto42]

Invalid UTF-8 characters in names at the bottom of the file:

• [Maître Mô](​http://maitremo.fr/) (French)
• Bar¿¿ Ünver (Turkish)
• Fredrik Forséll (Swedish)

[tellyworth]

In 4486:

Plugin directory: handle invalid UTF8 when parsing and validating readme.

Fixes #2298