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; }};

llvm-svn: 209410