clang-format: Fix alignment of comments inside statements.

Before:
  auto result = SomeObject
                // Calling someFunction on SomeObject
                    .someFunction();

After:
  auto result = SomeObject
                    // Calling someFunction on SomeObject
                    .someFunction();

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@201138 91177308-0d34-0410-b5e6-96231b3b80d8