Change: Except for the initial release operation,
a release sequence consists solely of atomic read-modify-write operations.
Rationale: Removal of rarely used and confusing feature.
Effect on original feature: If a memory_order_release atomic store is followed
by a memory_order_relaxed store to the same variable by the same thread,
then reading the latter value with a memory_order_acquire load
no longer provides any “happens before” guarantees,
even in the absence of intervening stores by another thread.