Revert "coredump: Use the vma snapshot in fill_files_note"

This reverts commit 39fd0cc0.

It breaks the kernel abi so revert it for now.  We will add it back
later at the next kabi update.

Bug: 161946584
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I0c97342054fad52bd957a09f48a176e71d76ec01