[android] do not import stdatomic from android's libc++

[hyp]

android's libc++ uses an older module map that requires C++23 for stdatomic, and thus it fails to compile with anything else

not quite sure why this worked in the initial testing, but after some changes in LLVM/Swift the Android import requires stdatomic not to come from libc++ as it has an outdated requirement.

[hyp]

CC @finagolfin as well

[hyp]

@swift-ci please test

[finagolfin]

I don't use C++ interop myself so I don't know much about this issue: @egorzhdan or someone else will have to review.

Some good news though: I tracked down the change in the Termux headers that was causing the Swift/C++ interop issue there, along with a bizarre function overloading issue in the libc++ headers that I simply commented out for now. I will run the full Swift compiler validation suite in Termux next and see if those Termux header changes fix most of the C++ interop issues I have been seeing in Termux.

[hyp]

Some good news though: I tracked down the change in the Termux headers that was causing the Swift/C++ interop issue there, along with a bizarre function overloading issue in the libc++ headers that I simply commented out for now. I will run the full Swift compiler validation suite in Termux next and see if those Termux header changes fix most of the C++ interop issues I have been seeing in Termux.

Cool, that sounds good!

I will merge this in, to unblock further testing and cherry-picking the Android changes to swift 6.