Remove presubmit check for DISALLOW_* macros
Remove presubmit check for DISALLOW_* macros

Before C++11, we were using a hack to disable copy constructors or copy
assignment by declaring the methods private and not implementing them.
This hack required the respective macros to be placed in the private:
declarations of a class.
The macros have switched to use the C++11 "= delete" syntax some time
ago in both v8 and chromium:
https://codereview.chromium.org/1123723003/
https://codereview.chromium.org/2017213002

Also the comments are now updated, since the macros do not need to be
in the private: declarations any more:
https://chromium-review.googlesource.com/c/577687
https://chromium-review.googlesource.com/c/578027

This change also removes the presubmit check that checked that the
macros are only used in the private declarations.

theandrewdavis/cpplint