Add trace and registers stages.

Yet more debugging tools.

TBR=herb@google.com

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4908
CQ_INCLUDE_TRYBOTS=master.client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot

Change-Id: I92e2e6b17abfc32c8d3554e71dbf95abadbb3824
Reviewed-on: https://skia-review.googlesource.com/4908
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Herb Derby <herb@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
2 files changed