[libFuzzer] improve -reduce_inputs=1: now only consider the unique features of very input (seems to work much better)

git-svn-id: svn://svn.chromium.org/llvm-project/llvm/trunk/lib/Fuzzer@308253 0b72dbe1-c17f-4bc7-b9db-2b4152be0356
4 files changed