clang-format: Correctly calculate line lenghts for nest blocks.

If simple (one-statement) blocks can be inlined, the length needs to be
calculated correctly.

Before (in JavaScript but this also affects lambdas, etc.):
  var x = {
    valueOf: function() { return 1; }
  };

After:
  var x = {valueOf: function() { return 1; }};

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209410 91177308-0d34-0410-b5e6-96231b3b80d8