Remove thread local for mach port (#3119)

This was needed a long time ago in the original implementation when the
function being called here was hotter than it was before, but nowadays
this function isn't hot as it's protected elsewhere from being
repeatedly called, so the caching thread local is no longer necessary.

crates/runtime/src/traphandlers/macos.rs

@@ -392,20 +392,6 @@ unsafe extern "C" fn unwind(wasm_pc: *const u8) -> ! {
     wasmtime_longjmp(jmp_buf);
 }
 
-thread_local! {
-    static MY_PORT: ClosePort = ClosePort(unsafe { mach_thread_self() });
-}
-
-struct ClosePort(mach_port_name_t);
-
-impl Drop for ClosePort {
-    fn drop(&mut self) {
-        unsafe {
-            mach_port_deallocate(mach_task_self(), self.0);
-        }
-    }
-}
-
 /// Exceptions on macOS can be delivered to either thread-level or task-level
 /// exception ports. In wasmtime we choose to send the exceptions to
 /// thread-level ports. This means that we need to, for each thread that can
@@ -426,13 +412,15 @@ impl Drop for ClosePort {
 pub fn lazy_per_thread_init() -> Result<(), Trap> {
     unsafe {
         assert!(WASMTIME_PORT != MACH_PORT_NULL);
+        let this_thread = mach_thread_self();
         let kret = thread_set_exception_ports(
-            MY_PORT.with(|p| p.0),
+            this_thread,
             EXC_MASK_BAD_ACCESS | EXC_MASK_BAD_INSTRUCTION,
             WASMTIME_PORT,
             EXCEPTION_DEFAULT | MACH_EXCEPTION_CODES,
             mach_addons::THREAD_STATE_NONE,
         );
+        mach_port_deallocate(mach_task_self(), this_thread);
         assert_eq!(kret, KERN_SUCCESS, "failed to set thread exception port");
     }
     Ok(())