Turn on -Wrange-loop-analysis.

Turn on -Wrange-loop-analysis.

-Wrange-loop-analysis triggers when we use a new-style for loop in a way that appears to unintentionally call a copy constructor on each non-trivial loop element instead of operating on them by reference.

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4000

Change-Id: If9e1b7fcc1f2789ae03c41c17abb17e60d564a8b
Reviewed-on: https://skia-review.googlesource.com/4000
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>