[InstCombine] Reformat if statements to comply with LLVM Coding Standards.

Patch by Sonam Kumari!

Differential Revision: http://reviews.llvm.org/D5643

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219198 91177308-0d34-0410-b5e6-96231b3b80d8