memory from the OS to deserialize the initial heap snapshot at
startup.

This catches the failure to startup earlier, and avoids dereferencing
the encoding of an allocation failure.

BUG=16359

Review URL: http://codereview.chromium.org/159265

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2526 ce2b1a6d-e550-0410-aec6-3dcde31c8c00