Clean up warnings in Windows build

[ttjsu-aws]

..\tests\integration\t_local_cache_threading.c(85): warning C4244: 'return': conversion from 'uint64_t' to 'unsigned long', possible loss of data
..\tests\integration\t_local_cache_threading.c(116): warning C4113: 'unsigned long (__cdecl *)()' differs in parameter lists from 'unsigned long (__cdecl *)(void)'