Fix memory sharing (#2415)

- Inherit shared memory from the parent instance, instead of
  trying to look it up by the underlying module. The old method
  works correctly only when every cluster uses different module.
- Use reference count in WASMMemoryInstance/AOTMemoryInstance
  to mark whether the memory is shared or not
- Retire WASMSharedMemNode
- For atomic opcode implementations in the interpreters, use
  a global lock for now
- Update the internal API users
  (wasi-threads, lib-pthread, wasm_runtime_spawn_thread)

Fixes https://github.com/bytecodealliance/wasm-micro-runtime/issues/1962

core/iwasm/interpreter/wasm_runtime.h

@@ -7,6 +7,7 @@
 #define _WASM_RUNTIME_H
 
 #include "wasm.h"
+#include "bh_atomic.h"
 #include "bh_hashmap.h"
 #include "../common/wasm_runtime_common.h"
 #include "../common/wasm_exec_env.h"
@@ -79,7 +80,7 @@ struct WASMMemoryInstance {
     /* Module type */
     uint32 module_type;
     /* Shared memory flag */
-    bool is_shared;
+    bh_atomic_32_t ref_count; /* 0: non-shared, > 0: reference count */
 
     /* Number bytes per page */
     uint32 num_bytes_per_page;
@@ -400,7 +401,7 @@ void
 wasm_unload(WASMModule *module);
 
 WASMModuleInstance *
-wasm_instantiate(WASMModule *module, bool is_sub_inst,
+wasm_instantiate(WASMModule *module, WASMModuleInstance *parent,
                  WASMExecEnv *exec_env_main, uint32 stack_size,
                  uint32 heap_size, char *error_buf, uint32 error_buf_size);