[libFuzzer] Run libFuzzer unit tests only on host architecture.

LIT tests are used to test other cross-compiled architectures,
unit tests are only run on the host.
NFC now as currently only a single architecture is supported.

Differential Revision: https://reviews.llvm.org/D47286

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk/lib/fuzzer@333241 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed