Use runtime.numCPU() workers in concurrent benchmarks, remove pointless benchmarks for racy maps, and add replacement benchmarks using mutexed maps
Use runtime.numCPU() workers in concurrent benchmarks, remove pointless benchmarks for racy maps, and add replacement benchmarks using mutexed maps

yxd-hde/go-cache,robfig/go-cache,pmylund/go-cache,nothingmuch/go-cache,cognusion/go-cache-lru,ggaaooppeenngg/cachemap,zj8487/go-cache,patrickmn/go-cache,jiangjin/go-cache