RFR: 8306966: RISC-V: Support vector cast node for Vector API [v8]

[Gui Cao]

On Sun, 7 May 2023 02:02:56 GMT, Feilong Jiang <fjiang at openjdk.org> wrote:

> Should we add `assert_differrent_registers` to prevent the same vector register used by other ppl?

has been modified and the src and dst registers can now be the same.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13684#discussion_r1186783569