Define a dedicated `vmvar_t` type for values stored in variable pages
and propagate it through interfaces that expose those values. Keep the
type as int for now so this commit does not change runtime behavior.
This separates VM storage from ordinary int buffers and makes a later
conversion to 16-bit storage mechanically checkable.
- Add some functions to ASYNCIFY_ADD
A function that calls an asynchronous function via a function pointer
must be added to ASYNCIFY_ADD, even if it had a direct call to
another asynchronous function, so that the indirect call itself is
instrumented.
- Add dummy emscripten_sleep() call to send_agsevent
Because adding a function to ASYNCIFY_ADD does not make its callers
instrumented transitively.
kichikuou