Merge pull request #33003 from tchaikov/wip-buffer-list-advance

include/buffer: add operator+=() for list::iterator

Reviewed-by: Radoslaw Zarzynski <rzarzyns@redhat.com>

diff --cc src/common/buffer.cc
Simple merge

diff --cc src/include/buffer.h
Simple merge

diff --cc src/osd/PrimaryLogPG.cc
Simple merge

diff --cc src/osd/osd_types.cc
Simple merge

diff --cc src/test/bufferlist.cc
Simple merge