When the toolchain has picolibc support, run
samples/subsys/cpp/cpp_synchronization and tests/subsys/cpp/libcxx tests
using it.
Signed-off-by: Keith Packard <keithp@keithp.com>
This commit moves the C++ samples under `samples/subsys/cpp` to
`samples/cpp` because the C++ language and standard library support is
not a "subsystem" (aka. API) in conventional sense and the samples
demonstrating them should belong directly under the top samples
directory as does POSIX support.
Signed-off-by: Stephanos Ioannidis <stephanos.ioannidis@nordicsemi.no>