Update checkstyle rules.

- Change catching Exepction and Throwable as warnings.
- Allow comments for EmptyBlocks
- Allow empty methods and contructors.
- Set using finalizer as a warning.

BUG=318404
NOTRY=true

Review URL: https://codereview.chromium.org/81903002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236630 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236630