PR libstdc++/56012
	* include/bits/atomic_base.h (atomic_flag): Fix narrowing conversion.
	* testsuite/29_atomics/atomic/operators/56012.cc: New.

	PR libstdc++/56011
	* include/std/atomic (atomic<bool>::operator=(bool) volatile): Add
	missing overload.
	* testsuite/29_atomics/atomic/operators/56011.cc: New.

From-SVN: r196296