gitweb: Remove gitweb/test/ directory

gitweb: Remove gitweb/test/ directory

Testing if gitweb handles filenames with spaces, filenames with plus
sign ('+') which encodes spaces in CGI parameters (in URLs), and
filenames with Unicode characters should be handled by gitweb tests.

Those files are remainder of the time when gitweb was project on its
own, not a part of git (with its testsuite).

Signed-off-by: Jakub Narebski <redacted>
Signed-off-by: Junio C Hamano <redacted>