More clang-tidy suggested fixes

I also spotted some SkAssertResults that really should be SkASSERT

Change-Id: I232c574a796ba598342911c30239962ee01697c0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/815937
Reviewed-by: Nicolette Prevost <nicolettep@google.com>
7 files changed