Dump bitmap from BlurTests on failure

And sample inside the blur gradient first so it's more likely to trip
the screenshot dump on the more interesting part.

Bug: 204943505
Bug: 205597389
(cherry picked from https://android-review.googlesource.com/q/commit:c375bba82d42d99756221de89d0d209d691a29fb)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:b4e34eed55e2a4acd9e0e8c520855b06209dc2e6)
Merged-In: Ic25f605562b639426a6af838961bbe67b439ffd2
Change-Id: Ic25f605562b639426a6af838961bbe67b439ffd2
1 file changed