[AFL] Allow webrtc fuzzers to be used with afl-fuzz.

BUG=chromium:611337

Review-Url: https://codereview.webrtc.org/2143053002
Cr-Commit-Position: refs/heads/master@{#13519}

setup_links.py

diff --git a/setup_links.py b/setup_links.py
index 4cf91f7..861ef71 100755
--- a/setup_links.py
+++ b/setup_links.py
@@ -33,6 +33,7 @@
   'buildtools',
   'mojo',  # TODO(kjellander): Remove, see webrtc:5629.
   'testing',
+  'third_party/afl',
   'third_party/binutils',
   'third_party/boringssl',
   'third_party/colorama',