Fix some Clang-tidy modernize-use-default and readability-redundant-member-init and Include What You Use warnings; other minor fixes.

Differential revision: https://reviews.llvm.org/D26087


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286484 91177308-0d34-0410-b5e6-96231b3b80d8
8 files changed