Free FontChains after test completes

ASAN detected this leak.

Change-Id: I7f54cbe35ac36d288d2fa676cf0192a793686ba1
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/526077
Reviewed-by: Julia Lavrova <jlavrova@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
2 files changed