clang-format: Improve boolean expression formatting in macros.

Before:
  #define IF(a, b, c) if (a&&(b == c))

After:
  #define IF(a, b, c) if (a && (b == c))

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188256 91177308-0d34-0410-b5e6-96231b3b80d8