RFR: 8259948: Aarch64: Add cast nodes for Aarch64 Neon backend

[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.

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Commit messages:
 - fix bugs
 - 8259948: Aarch64: Add cast nodes for Aarch64 Neon backend

Changes: https://git.openjdk.java.net/jdk/pull/4839/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4839&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8259948
  Stats: 615 lines in 6 files changed: 493 ins; 21 del; 101 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