Remove known failures from arm ifunc tests

Since clang does not produce IRELATIVE relocations
this test started passing when we switched away from gcc
This is still a problem because it now leads to
situation where static ifuncs become globally visible
but this is a different problem.

Test: bionic-unit-tests --gtest_filer=dl*
Change-Id: Id27ba5093b88519c00acbc43ab8a991a671a9f51