[clang-tidy] Sequence init statements, declarations, and conditions correctly...

[clang-tidy] Sequence init statements, declarations, and conditions correctly in if, switch, and while

Summary: Fixes https://bugs.llvm.org/show_bug.cgi?id=36516.

Reviewers: ilya-biryukov, alexfh, aaron.ballman, hokein

Reviewed By: alexfh

Subscribers: xazax.hun, cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D49918

llvm-svn: 338932