clang-format: Fix corner case for brace alignment.

Before:
  Constructor::Constructor()
      : some_value{ //
            aaaaaaa //
  } {}

After:
  Constructor::Constructor()
      : some_value{ //
            aaaaaaa //
        } {}

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194204 91177308-0d34-0410-b5e6-96231b3b80d8