Run profile tests on FreeBSD

FreeBSD does not have libdl, so set it via lit.cfg instead of the test
input, as with asan.  Also remove it from Darwin test runs - it's not
necessary, but harmless there.

Add FreeBSD to the list of hosts to test.

Differential Revision: http://reviews.llvm.org/D5650


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@219227 91177308-0d34-0410-b5e6-96231b3b80d8