Remove [[unlikely]] attribute.

This causes build breakage in google3:
- use of the 'unlikely' attribute is a C++20 extension [-Werror,-Wc++20-attribute-extensions]

Change-Id: I534b6673bbe90a040c8485e9795a9cdcb5d1d9dd
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/607659
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Tyler Denniston <tdenniston@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Tyler Denniston <tdenniston@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
1 file changed