[test] Suppress new lint check

TBR=mstarzinger@chromium.org,bmeurer@chromium.org
NOTRY=true

Review-Url: https://codereview.chromium.org/2605113002
Cr-Commit-Position: refs/heads/master@{#41983}

tools/presubmit.py

@@ -62,6 +62,7 @@ LINT_RULES = """
 -build/include_what_you_use
 -build/namespaces
 -readability/check
+-readability/fn_size
 +readability/streams
 -runtime/references
 """.split()