Optimize GetRandomStr
Optimize GetRandomStr

Closes #4489.

PiperOrigin-RevId: 184532916

dslomov/bazel,werkt/bazel,dslomov/bazel,meteorcloudy/bazel,akira-baruah/bazel,ulfjack/bazel,dslomov/bazel-windows,davidzchen/bazel,aehlig/bazel,twitter-forks/bazel,safarmer/bazel,dslomov/bazel-windows,werkt/bazel,akira-baruah/bazel,perezd/bazel,safarmer/bazel,ulfjack/bazel,dslomov/bazel,dslomov/bazel-windows,dropbox/bazel,safarmer/bazel,aehlig/bazel,katre/bazel,meteorcloudy/bazel,katre/bazel,katre/bazel,bazelbuild/bazel,ButterflyNetwork/bazel,meteorcloudy/bazel,ulfjack/bazel,davidzchen/bazel,cushon/bazel,bazelbuild/bazel,dslomov/bazel-windows,davidzchen/bazel,ulfjack/bazel,dslomov/bazel,meteorcloudy/bazel,dropbox/bazel,dslomov/bazel,werkt/bazel,aehlig/bazel,cushon/bazel,bazelbuild/bazel,aehlig/bazel,dslomov/bazel-windows,akira-baruah/bazel,ulfjack/bazel,davidzchen/bazel,ButterflyNetwork/bazel,ulfjack/bazel,dropbox/bazel,cushon/bazel,safarmer/bazel,twitter-forks/bazel,dropbox/bazel,werkt/bazel,dslomov/bazel,twitter-forks/bazel,davidzchen/bazel,twitter-forks/bazel,perezd/bazel,ButterflyNetwork/bazel,ButterflyNetwork/bazel,meteorcloudy/bazel,perezd/bazel,safarmer/bazel,perezd/bazel,aehlig/bazel,davidzchen/bazel,bazelbuild/bazel,werkt/bazel,katre/bazel,katre/bazel,meteorcloudy/bazel,dropbox/bazel,bazelbuild/bazel,werkt/bazel,twitter-forks/bazel,aehlig/bazel,perezd/bazel,meteorcloudy/bazel,akira-baruah/bazel,ButterflyNetwork/bazel,dropbox/bazel,twitter-forks/bazel,aehlig/bazel,ButterflyNetwork/bazel,twitter-forks/bazel,bazelbuild/bazel,perezd/bazel,dslomov/bazel,dslomov/bazel-windows,cushon/bazel,cushon/bazel,perezd/bazel,davidzchen/bazel,akira-baruah/bazel,katre/bazel,ulfjack/bazel,safarmer/bazel,cushon/bazel,akira-baruah/bazel