[fuzzer] fix the missing parenthesis

R=machenbach@chromium.org
CC=​yangguo@chromium.org,sergiyb@chromium.org

No-Try: True
Bug: v8:8174
Change-Id: Ia77a42f3dce741f661f3d7aee3af2237e53ae0f0
Reviewed-on: https://chromium-review.googlesource.com/c/1447713Reviewed-by: Sergiy Belozorov <sergiyb@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Tamer Tas <tmrts@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59233}

tools/testrunner/num_fuzzer.py

@@ -153,7 +153,7 @@ class NumFuzzer(base_runner.BaseTestRunner):
       execproc,
     ]
     self._prepare_procs(procs)
-    loader.load_tests(tests, initial_batch_size=float('inf')
+    loader.load_tests(tests, initial_batch_size=float('inf'))
 
     # TODO(majeski): maybe some notification from loader would be better?
     if combiner: