[LibFuzzer] Move tests in ``fuzzer-traces.test`` that require hooks to their own test.

The tests in ``fuzzer-traces-hooks.test`` only work on Linux because calls to hooks
(e.g. ``__sanitizer_weak_hook_memcmp()``) from inside the sanitizer
runtime are only implemented on Linux. Therefore these tests are set to
only run on Linux.

Differential Revision: http://reviews.llvm.org/D21253

llvm-svn: 272600