Revert "Driver bug workaround: disable_blend_equation_advanced"

This reverts commit f31fece6581a46b40403fc78c83c7eebe50816ba.

Reason for revert: need to revert to revert original change breaking chrome compile

Original change's description:
> Driver bug workaround: disable_blend_equation_advanced
> 
> Bug: chromium: 829614
> Change-Id: If8eaec6d22412ec36aad8a143f84080be05f2926
> Reviewed-on: https://skia-review.googlesource.com/126748
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Adrienne Walker <enne@chromium.org>

TBR=bsalomon@google.com,enne@chromium.org

Change-Id: Ic870fbbad615d13569254c355ef6b8281332d60d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium: 829614
Reviewed-on: https://skia-review.googlesource.com/127301
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
4 files changed