Try to fix x86_64-apple-darwin release builds (#12245)

This is an attempt to address #12217 which applies a similar workaround
found in #11960 to this naked function as well. Effectively it looks
like `#[unsafe(naked)]` is buggy to the point that the user of the
function symbol must be `#[inline(never)]` and in the same module,
otherwise it won't work correctly.

Closes #12217

Author: alexcrichton

crates/wasmtime/src/runtime/vm/stack_switching/stack/unix.rs

@@ -258,7 +258,7 @@ impl VMContinuationStack {
 
             let to_store = [
                 // Data near top of stack:
-                (0x08, (wasmtime_continuation_start as *const ()).addr()),
+                (0x08, wasmtime_continuation_start_address().addr()),
                 (0x10, tos.sub(0x10).addr()),
                 (0x18, tos.sub(0x40 + args_data_size).addr()),
                 (0x20, usize::try_from(args_capacity).unwrap()),

crates/wasmtime/src/runtime/vm/stack_switching/stack/unix/x86_64.rs

@@ -7,6 +7,11 @@
 
 use core::arch::naked_asm;
 
+#[inline(never)] // FIXME(rust-lang/rust#148307)
+pub fn wasmtime_continuation_start_address() -> *const () {
+    wasmtime_continuation_start as *const ()
+}
+
 // This is a pretty special function that has no real signature. Its use is to
 // be the "base" function of all fibers. This entrypoint is used in
 // `wasmtime_continuation_init` to bootstrap the execution of a new fiber.