[Hexagon] Add Hexagon Copy Hoisting pass (#89313)

Adds the HexagonCopyHoisting pass, which moves a common copy instruction
into a basic block if it is present in all successor basic blocks.

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Co-authored-by: Jyotsna Verma <jverma@quicinc.com>
GitOrigin-RevId: cb508a0032eb2d11391214864f408261158361bf
4 files changed