[fuzzer] fix missing argument

R=machenbach@chromium.org

No-Try: true
Change-Id: Iadb464e55fd30cc01ad6f250efd01588610407d0
Reviewed-on: https://chromium-review.googlesource.com/c/1449534
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59274}

tools/testrunner/num_fuzzer.py

@@ -127,7 +127,7 @@ class NumFuzzer(base_runner.BaseTestRunner):
     return variables
 
   def _do_execute(self, tests, args, options):
-    loader = LoadProc()
+    loader = LoadProc(tests)
     fuzzer_rng = random.Random(options.fuzzer_random_seed)
 
     combiner = self._create_combiner(fuzzer_rng, options)