RFR: 8259948: Aarch64: Add cast nodes for Aarch64 Neon backend [v2]

[Wang Huang]

> * In this issue, we plan to complete all missing implementation for aarch64 neon backend. For example, cast from Byte to Long, cast from Long to Byte, and so on.
> * It may be a solver of JDK-8269866, or part of it.

Wang Huang has updated the pull request incrementally with one additional commit since the last revision:

  fix code style

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4839/files
  - new: https://git.openjdk.java.net/jdk/pull/4839/files/aa46faec..620e4956

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4839&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4839&range=00-01

  Stats: 120 lines in 5 files changed: 14 ins; 43 del; 63 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4839.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4839/head:pull/4839

PR: https://git.openjdk.java.net/jdk/pull/4839