socket module should use PyMutex instead of Lock

@kumaraditya303

Issue

This is a follow-up from #150406 where @kumaraditya303 pointed out that the existing Lock allocated here...

Lines 9294 to 9296 in a189e3d

    
           #if defined(USE_GETHOSTBYNAME_LOCK) 
        
               netdb_lock = PyThread_allocate_lock(); 
        
           #endif

... should be replaced with a PyMutex.

gh-150452: use PyMutex in socket module (#150453)

	#if defined(USE_GETHOSTBYNAME_LOCK)
	netdb_lock = PyThread_allocate_lock();
	#endif