Remove cmake/

We've stopped testing and updating the experimental CMakeLists.txt file.

A guide to building Skia with GN is available at skia.org/user/build.

Change-Id: I3d3f8f2254f072b0520bd7a9b810c4e13b871680
Reviewed-on: https://skia-review.googlesource.com/5334
Reviewed-by: Heather Miller <hcm@google.com>
Commit-Queue: Heather Miller <hcm@google.com>
5 files changed