Remove redundant comma

Author: kleisauke

src/library_pthread.js

@@ -9,7 +9,7 @@ var LibraryPThread = {
   $PThread__deps: ['_emscripten_thread_init',
                    'emscripten_register_main_browser_thread_id',
                    '$ERRNO_CODES', 'emscripten_futex_wake', '$killThread',
-                   '$cancelThread', '$cleanupThread',
+                   '$cancelThread', '$cleanupThread'
 #if USE_ASAN || USE_LSAN
                    , '$withBuiltinMalloc'
 #endif