After 6083a2706d55, it is possible to determine the expected size of a
versioned structure such as dyld_all_image_infos. The expected size is
compared against the actual size of the structure as returned by
task_info() (TASK_DYLD_INFO).
TEST=crashpad_snapshot_test
R=rsesek@chromium.org
Review URL: https://codereview.chromium.org/1272283004 .