[milr][gpu] Make barrier elimination address-space aware (#178101)

Upgrade the barrier eliminiation pass to account for the address spaces
of accessed memory when deciding which barriers to eliminiate. In
particular, a loop that only reads and writes global memory that has a
workgoup-memory-fencing barrier inside of it will now have that barrier
marked for elimiination, as the global memory traffic is not being
synchronized by the barrier.

The pass is also adjusted to ignore barriers whose memory fencing list
is [], as those do not synchronize memory and therefore the logic in
this pass would potentially incorrectly remove them after proving that
fact.

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Co-authored-by: Jakub Kuderski <kubakuderski@gmail.com>
GitOrigin-RevId: c08b2c75dbc4aae897affa8d38108d779350e137