ANDROID: cfi: fix shadow rebasing

If the module area base address changes when loading a new module, the
new CFI shadow will only cover the first allocated page for each existing
module. This will cause cross-DSO look-ups to functions elsewhere in the
module to fall back to a red-black tree, which may be slower.

Bug: 122963951
Change-Id: I9262034d39351afcd42590ead8d6384fc30a8ce8
Reported-by: Wu,Le <wule01@baidu.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>