If the outer classifier will end up parsing an arrow parameter list we'd only
be in an inner classifier if the outer was already known to be non-simple.

Change-Id: I9fdfb5539b3a7989869f7190f0919699fe8e5c90
Reviewed-on: https://chromium-review.googlesource.com/c/1276630Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56589}