Remove duplicate simple samples, make one a gm.

SampleBigBlur is super simple and now covered by gms and AnimBlur
sample.

SampleBigGradient now has a gm shallow_gradient_linear.

SampleConcavePaths has a more complete gm concavepaths.

SamplePoints now has an almost exact gm.

RasterAllocatorSample is made into a gm so that it will be run by d. It
appears to be the only test of SkRasterHandleAllocator, so it should
probably run.

Change-Id: Iad7b99d0f92898fc4b2fdccc5aae35d0277f2fff
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/219400
Reviewed-by: Hal Canary <halcanary@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
6 files changed