Use a symbolic constant for the default thread count. Bug 23073037 Change-Id: I7da215ceff23f9a5c8188d3566a7c478b9489117 Reviewed-on: https://swiftshader-review.googlesource.com/3841 Reviewed-by: Alexis Hétu <sugoi@google.com> Reviewed-by: Nicolas Capens <capn@google.com> Tested-by: Nicolas Capens <capn@google.com>