SkQP: refatctor C++ bits.

  * C++ code moved into tools/skqp/src/.
  * State held with single SkQP class.
  * gmkb functions moved to skqp_model.{h,cpp}
  * model no longer knows about report format.
  * skqp_main and skqp_lib no longer have globals
  * jni code has fewer globals.
  * skqp_main no longer uses googletest.
  * AssetMng returns SkData, not a SkStream.
  * Add jitter tool.
  * dump GPU information into grdump.txt
  * JUnit puts report in directory with timestamp.
  * Document SkQP Render Test Algorithm.
  * GPU driver correctness workarounds always off
  * cut_release tool for assembling models
  * make_rendertests_list.py to help cut_release
  * make_gmkb.go emits a list of models

CQ_INCLUDE_TRYBOTS=skia.primary:Build-Debian9-Clang-x86-devrel-Android_SKQP

Change-Id: I7d4f0c24592b1f64be0088578a3f1a0bc366dd4d
Reviewed-on: https://skia-review.googlesource.com/c/110420
Reviewed-by: Hal Canary <halcanary@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
34 files changed