gh-84461: Fix ctypes and test_ctypes on Emscripten (GH-94142)

- c_longlong and c_longdouble need experimental WASM bigint.
- Skip tests that need threading
- Define ``CTYPES_MAX_ARGCOUNT`` for Emscripten. libffi-emscripten 2022-06-23 supports up to 1000 args.
(cherry picked from commit 8625802d85)

Co-authored-by: Christian Heimes <christian@python.org>

Modules/_ctypes/ctypes.h

@@ -19,7 +19,11 @@
  * to avoid allocating a massive buffer on the stack.
  */
 #ifndef CTYPES_MAX_ARGCOUNT
-  #define CTYPES_MAX_ARGCOUNT 1024
+  #ifdef __EMSCRIPTEN__
+    #define CTYPES_MAX_ARGCOUNT 1000
+  #else
+    #define CTYPES_MAX_ARGCOUNT 1024
+  #endif
 #endif
 
 typedef struct tagPyCArgObject PyCArgObject;