[clang-tidy] new check: bugprone-branch-clone
Implement a check for detecting if/else if/else chains where two or more
branches are Type I clones of each other (that is, they contain identical code)
and for detecting switch statements where two or more consecutive branches are
Type I clones of each other.
Patch by donat.nagy.
Reviewers: alexfh, hokein, aaron.ballman, JonasToth
Reviewed By: JonasToth
Subscribers: MTC, lebedev.ri, whisperity, xazax.hun, Eugene.Zelenko, mgorny, rnkovacs, dkrupp, Szelethus, gamesh411, cfe-commits
Differential Revision: https://reviews.llvm.org/D54757