clang-format: Fix braced list detection.

Before:
  static_assert(std::is_integral<int> {} + 0, "");
  int a = std::is_integral<int> {}
  + 0;

After:
  static_assert(std::is_integral<int>{} + 0, "");
  int a = std::is_integral<int>{} + 0;

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209431 91177308-0d34-0410-b5e6-96231b3b80d8