RFR: 8350329: C2: Div looses dependency on condition that guarantees divisor not zero in counted loop after peeling

[Roland Westrelin]

This is an issue similar to 8349139: the type of the iv phi of a
counted loop is narrowed down so a `Div` node doesn't need a control
input. The loop is then peeled. The `Div` in the loop body is
guaranteed to be non zero only if it is actually executed so the `Div`
is implicitly dependent on the zero trip guard. Then the loop looses
its backedge and the `Div` freely floats. The `Div` instruction is
scheduled above the zero trip guard and faults. Had the `Div` been
control dependent on the zero trip guard, it wouldn't have
executed. The fix, similar to 8349139 is to add a `CastII` on peeling
to make the dependency between what's in the loop body and relies on
the narrowed down type of the iv phi and the zero trip guard explicit.

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Commit messages:
 - test
 - fix

Changes: https://git.openjdk.org/jdk/pull/25262/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25262&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8350329
  Stats: 62 lines in 2 files changed: 60 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/25262.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25262/head:pull/25262

PR: https://git.openjdk.org/jdk/pull/25262