Fix SkTLazy(const T*) initialization

Splitting the fix from https://codereview.chromium.org/2271743002/.

R=bungeman@google.com,mtklein@google.com
TBR=reed@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2278633002

Review-Url: https://codereview.chromium.org/2278633002
1 file changed