clang-format: Fix aligning of comments and escaped newlines in macros.

Before:
  #define A      \
    int i;   /*a*/ \
    int jjj; /*b*/

After:
  #define A        \
    int i;   /*a*/ \
    int jjj; /*b*/

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@205011 91177308-0d34-0410-b5e6-96231b3b80d8