[jetski] Fix gn/gradle builds

Add SkWindowContext GN build file, and fix JetSki->jetski Gradle naming.

Change-Id: Ie79bed22c49eae27b6aa595ec14940f20127385c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/688016
Reviewed-by: Jorge Betancourt <jmbetancourt@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
4 files changed