Enable shrunk memory by default and add related configurations (#4008)

- Enable shrunk memory by default and add related configurations
- Improve error messages for memory access alignment checks
- Add documentation for WAMR shrunk memory build option
- Update NuttX workflow to disable shrunk memory build option

core/config.h

@@ -698,4 +698,8 @@
 #define WASM_ENABLE_SHARED_HEAP 0
 #endif
 
+#ifndef WASM_ENABLE_SHRUNK_MEMORY
+#define WASM_ENABLE_SHRUNK_MEMORY 1
+#endif
+
 #endif /* end of _CONFIG_H_ */