PHPUnit FilterTest failing incorrectly

The test was using a function to returning the 1st 50 issues for all
projects. In a DB containing more than 50 issues, the test would fail
incorrectly.

Now using a filter on the current project only.
PHPUnit HelperTest fix error 4096

Commit 5458f7020999317b35f403fa2a0e477d6182ec12 changed function
helper_array_transpose() signature, the argument MUST be an array so it
does not make sense for the unit test to cover NULL, Scalar and Object
types.
Fix #17751: add 'UTC' to timezone selection list

Also fixes the list for timezones containing a '/' in the name (e.g.
Argentina/xxx)
Fix timezone initialization in core.php

Prior to this, core.php would trigger a PHP warning on PHP >= 5.3 when
date_default_timezone_get() is not able to determine the timezone and
defaults to UTC (e.g. when php.ini date.timezone is not set).

The timezone is determined in the following order
  1. user preferences
  2. MantisBT configuration ($g_default_timezone)
  3. php.ini setting (date.timezone)
  4. UTC (set by date_default_timezone_get())

Fixes #17747
Revised admin check for $g_default_timezone

- Clarification of messages, added links to PHP documentation
- When default timezone is null, issue warning instead of failure and
  indicate defaulting to UTC
Update documentation for $g_default_timezone
Additional timezone init fixes

Implements additional fixes submitted by grangeway in PR #387

- Set installer_db_now() timezone to UTC
- Remove timezone_identifiers_list() existence checks
  These checks are obsolete, there were implemented to cover RHEL/CentOS
  under PHP 5.1 and we now require 5.3.
- Travis: set timezone to UTC

Signed-off-by: Damien Regad <dregad@mantisbt.org>
Set default timezone in install.php