Merge PR #31567 into master

* refs/pull/31567/head:
	common: move gen_rand_alphanumeric() helpers into common
	test: add unit tests for gen_rand_alphanumeric helpers

Reviewed-by: Adam C. Emerson <aemerson@redhat.com>

diff --cc src/rgw/rgw_common.cc
Simple merge

diff --cc src/rgw/rgw_rados.cc
Simple merge

diff --cc src/test/CMakeLists.txt
Simple merge