Always assert on calling proxied function from wasm worker. NFC

Follow up to #20135.

See #20135 (comment)

Author: sbc100

src/jsifier.js

@@ -247,7 +247,8 @@ if (ENVIRONMENT_IS_PTHREAD)
 ${body}
 }\n`
           });
-        } else if (WASM_WORKERS && ASSERTIONS) {
+        }
+        if (WASM_WORKERS && ASSERTIONS) {
           // In ASSERTIONS builds add runtime checks that proxied functions are not attempted to be called in Wasm Workers
           // (since there is no automatic proxying architecture available)
           snippet = modifyJSFunction(snippet, (args, body) => `

src/library.js

@@ -3769,7 +3769,7 @@ function wrapSyscallFunction(x, library, isWasi) {
   if (!WASMFS) {
     library[x + '__deps'].push('$SYSCALLS');
   }
-#if PTHREADS
+
   // Most syscalls need to happen on the main JS thread (e.g. because the
   // filesystem is in JS and on that thread). Proxy synchronously to there.
   // There are some exceptions, syscalls that we know are ok to just run in
@@ -3782,5 +3782,4 @@ function wrapSyscallFunction(x, library, isWasi) {
   if (library[x + '__proxy'] === undefined) {
     library[x + '__proxy'] = 'sync';
   }
-#endif
 }