Fix occurrences of "-Wextra-semi-stmt"

Docs-Preview: https://skia.org/?cl=173761
Change-Id: Iefdb91cd28eabb4b01b7b42a4f300b0b4caf05d9
Reviewed-on: https://skia-review.googlesource.com/c/173761
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
78 files changed