[MIPS] Fix library order and includes for breakpad test

Add missing header location for linux_dumper_unittest_helper for Android. It
is required to correctly locate sgidefs.h.
In addition, this change removes duplicate '-ldl', since the order of listed
libraries is important for GNU ld (still used for some architectures such as
MIPS).

BUG= fail to build breakpad tests for MIPS
TEST= build breakpad tests MIPS-Android

Review URL: https://codereview.chromium.org/26006002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227052 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 227052