[libFuzzer] Allow non-fuzzer args after -ignore_remaining_args=1

With this change, libFuzzer will ignore any arguments after a sigil
argument, but it will preserve these arguments at the end of the
command line when launching subprocesses. Using this, its possible to
handle positional and single-dash arguments to the program under test
by discarding everything up to -ignore_remaining_args=1 in
LLVMFuzzerInitialize.

git-svn-id: svn://svn.chromium.org/llvm-project/llvm/trunk/lib/Fuzzer@308069 0b72dbe1-c17f-4bc7-b9db-2b4152be0356
7 files changed