A few more variables were causing possible data races,
so they were changed to AtomicInt variables.

Change-Id: Icf233482528e086fc58f6919232ab2e3f0784689
Reviewed-on: https://swiftshader-review.googlesource.com/12368Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>