clang-format: Fix case-indentation in macros.

Before:
  #define OPERATION_CASE(name)           \
    case OP_name:                        \
    return operations::Operation##name

After:
  #define OPERATION_CASE(name)           \
    case OP_name:                        \
      return operations::Operation##name

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@189743 91177308-0d34-0410-b5e6-96231b3b80d8