[scudo] Move the chunk update into functions (#83493)

The code paths for mte enabled and disabled were interleaving and which
increases the difficulty of reading each path in both source level and
assembly level. In this change, we move the parts that they have
different logic into functions and minor refactors on the code
structure.

GitOrigin-RevId: 772b1b0cb26c66804d0a7e416dc7a5742b7f8db2
Change-Id: I74050e6b3c37365a58d70b48d4b1800da90ecc95
1 file changed