Format gd/os with new clang-format

find os -regex '.*\.\(cc\|h\|tpp\)' -exec clang-format -style=file -i {} \;

Test: cert/run --host
Bug: 156858180
Tag: #gd-refactor
Change-Id: I567f20faa1dee599bda4d9d6e7a8a16586574d6c