serialize/deserialize while/if ops using regions

This changes serialization and deserialization of while and if ops
to use regions instead of blocks.

also changed deserialization to preserve original ordering such that:
tosa1->deserialize->serialize->tosa2 => tosa1 == tosa2 most of the time.

Signed-off-by: Tai Ly <tai.ly@arm.com>
Change-Id: I539076788bdc466ba1881d955af349e6b4924ed8