Add support for Atomic{Bool} (Fix #26542). (#26597)
Adds `Bool` to list of types supported by `Atomic{T}`.
Defines all `atomic_*!` for `Bool`, except `atomic_add!` and `atomic_sub!`
since `add(::Bool, ::Bool)` returns an `Int`.
Also adds tests for those methods to `test/threads.jl`.
