Split cross-process transfer tests out of SitePerProcessBrowserTest.

BUG=none
R=mmenke@chromium.org

Review URL: https://codereview.chromium.org/185053007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255489 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255489