move generic parts of wasm_suspend_flags.h to bh_atomic.h

[yamt]

No description provided.

[loganek]

I'd expect bh_atomic to use stdatomics when possible; suspend_flag is an exception and should not use stdatomics (due to reasons explained in the linked PR). So my preference would be to keep those two separate, even if that means having some code duplicated (unless we do some ifdef's magic to only use builtin atomics in suspend_flag, but then I'm not sure if the complexity of code is worth the benefit we'll get).

[yamt]

I'd expect bh_atomic to use stdatomics when possible; suspend_flag is an exception and should not use stdatomics (due to reasons explained in the linked PR). So my preference would be to keep those two separate, even if that means having some code duplicated (unless we do some ifdef's magic to only use builtin atomics in suspend_flag, but then I'm not sure if the complexity of code is worth the benefit we'll get).

given how our aot compilation works, many of our runtime structures are
very sensitive to size/offset changes. it isn't only suspend_flags for which the "fixed-sized"
property can be convenient.

[wenyongh]

LGTM